HomeMy WebLinkAboutCOM 0391.005 2004-2006Harry Kim
'Ata) or
COUNTY OF HAWAII
Lincoln S.T. Ashida
Corporation Counsel
GeraldCakase
Assistant Corporation
Counsel
OFFICE OF THE CORPORATION COUNSEL
101 Aupuni Street, Suite 325 . Hilo, Hawaii 96720-4262 . (808) 961-8251 • Fax (808) 961-8622
PRIVILEGED AND CONFIDENTIAL COMMUNICATION
ATTORNEY-CLIENT COMMUNICATION
NOT A PUBLIC RECORD
August 16, 2005
MEMORANDUM
TO: Councilmember Bob Jacobson
Hawaii County Council
FR: Bobby Jean Leithead-Todd
Deputy Corporation Counsel
RE: Whether a Waste Reduction Facility Can Be Awarded a Sole Source Contract Instead of
Through an RFP and Whether an EIS Would Be Required For a "Clean" Technology
Corp. Counsel File No. WRK 05-10316
Question Presented:
May the County enter into a sole source contract with an alternative waste -to -energy
facility to remove and dispose of solid waste as an alternative to the current Hilo Landfill
because the vendor holds a patent to a "unique" technology?
Short Answer. -
No. Many waste -to -energy facilities hold patents to their technology. They all propose to
take most of the solid waste stream and convert it into either electricity or methane or ethanol or
other products. They all proffer themselves as a solution to the current problem of landfilling
trash. Selecting BRI Energy for a sole source contract would not hold up to any legal challenge.
Ouestion Presenter)
May the County enter into a sole source contract to dispose of solid waste through an
emergency purchase since the landfill may close in March 2006?
Short answer:
No. By definition, an emergency is an unforeseen or unexpected situation that requires
an immediate response. Some examples of emergencies would be hurricanes, tsunami, lava
inundation, and attacks from public enemies, strikes and earthquakes. Emergency procurement
Hawaii County is an Equal Opportunity Provider and Employer COMM. NO -
Ref *
O•Ref. To: Presex. ML
Ref. Dote AII_f
in such a situation would only be allowed to address the immediate, urgent needs created by the
emergency. The closure of the landfill has been foreseen for many years, and any intermediate
problems of dealing with municipal solid waste currently disposed of at the landfill can be
addressed by trucking the trash to Pu'uanahulu, where the County has a permitted landfill.
Contracting for disposal of solid waste is a long-term solution for a long-term problem, not a
short term emergency. The additional traffic generated by trucking the trash to Pu'uanahulu
could not be equated with emergencies such as earthquakes, hurricanes or acts of war as a basis
for doing an "emergency contract" that may be for a twenty-year period.
3. Question Presented.
Would an EIS be necessary, even if a vendor claims to use a completely "clean"
technology'?
Short answer:
Probably. A Chapter 343 environmental assessment ("EA") would be required at a
minimum and probably a full environmental impact statement ("EIS") would be required.
Chapter 343 is triggered whenever a proposed action involves the use of State or County finds or
land. Even if no state or county funding or lands were involved, a proposal to build a waste -to -
energy facility triggers Chapter 343. The purpose of the EA would be to ascertain whether an
EIS was required. Given the probability that either State or County land would be used to site
the facility, thus irrevocably committing such lands, County funds would need to be committed
for many years; and the fact that no similar facility has been permitted yet in Hawaii, as well as
the proximity of the proposed site to DHHL homesteads, and that the facility has to handle solid
waste, means a full EIS would probably be required.
Background:
On August 2, 2005, our office received a copy of a memorandum from Jung & Vassar
regarding the "necessity for Requests For Proposals (`RFP') for solid waste disposal contracts by
and between the County of Hawaii and private contractors." Mr. Jung posed two questions,
which he then proceeded to answer on behalf of his client. The first question was whether the
County was required to use an RFP for a contract to remove and dispose of solid waste from
existing landfills and transfer stations and/or the collection and disposal of solid waste by and
between commercial haulers and landfills and/or energy facilities. He answered that it was
possible to avoid doing an RFP through two possible exceptions to the procurement code, either
a sole source contract or an emergency contract. At another meeting with County officials,
Mr. Jung asserted that no EIS would be required for the facility, as it is a `clean" technology.
Sole Source Procurement
Sole source procurement is allowed under Section 103D-306 of the Hawaii Revised
Statutes when "the head of a purchasing agency determines in writing that there is only one
2
source for the required good, service, or construction, the determination is reviewed and
approved by the chief procurement officer, the written determination is posted in the maturer
described in rules adopted by the policy board, and no objection is outstanding."
Under the rules adopted by the policy board, the justification for sole source procurement
must establish that the good, service, or construction has a unique feature, characteristic, or
capability essential to the agency to accomplish its work and is available from one supplier or
source. HAR 3-122-81. Examples of goods or services that might qualify as sole source are
proprietary items, items with compatibility to existing equipment or public utility repair or
construction that can only be provided by the utility company. An item that is referred to by an
exact brand but has other brands that qualify as "equals" cannot be purchased as a sole source.
Items approved for sole source procurement which do not require the chief procurement
officer's approval are: (1) rental of booth space at conventions and trade shows when organized
by a single sponsor (when rental is only available through a single organizer or sponsor of the
convention or trade show); (2) the repair, replacement, installation (connection, activation or
hookup), or relocation of pubic utility company equipment or facilities (when equipment or
facilities are owned or controlled by utility companies such as an electric, telephone, gas, or
cable television company); (3) annual license renewal and maintenance for computer software
(when the license renewal and maintenance can be obtained from only a single source, normally
the developer of the software); procurement of computer software conversions, modifications,
and maintenance for existing programs from the manufacturer of the software (when the
conversion, modification, or maintenance can only be obtained from the manufacturer of the
software).
Mr. Jung has opined that the County could do a sole source contract with a company like
BRI Energy because they have a "patented" technology capable of "converting solid waste to
ethanol and electricity while reducing the mass of solid waste generated for disposal and the
need to transport the same to other transfer stations and landfills." Mr. Jung equates the holding
of a "patent" as sufficient to pass muster under a sole source analysis required under the
procurement c0-1-
In order to compare Mr. Jung's company with other waste -to -energy companies, our
office did a review of different technologies that are offering their services to various
municipalities. Some of the technologies listed as alternative technologies that were deemed not
ready to be considered as a viable option for New York were listed in a report entitled
"Evaluation of New and Emerging Solid Waste Management Technologies" that was published
in September 2004. Some of them are:
Arkenol Fuels - provides a patented, concentrated acid hydrolysis (waste to
ethanol) technology.
BRI Energy - thermal technology combines production of synthesis gas with air -
blown gasifier and biocatalytic fermentation of the synthesis gas for production of a high -
yield ethanol.
Changing World Technologies - owns a unique, patented technology that
converts organic waste into marketable, high quality fuels and specialty chemicals for
industrial and commercial use.
Eco Waste Solutions - offers a patented, thermal waste treatment process that
is based on the principles of pyrolysis.
Emerald Power/Isabella City - exclusive distributor of Bioconversion
Technology LLC's Pyrolytic Steam Reformer. The "Reformer" gasifies the organic
fraction of MSW in an oxygen -free reactor, producing a synthetic gas. The gas can be
burned to generate electricity, or through additional processing steps be reformulated into
fuel -grade ethanol.
ILS Partners/Pyromex - offers a patented Pyromex Waste -to -Energy technology.
Consists of a `gasifier reactor" that converts the organic fraction of MSW to -pyrogas"
that is combustible to generate electricity.
Zeros Technology Holding - Zeros is corporate acronym for "Zero -Emission
energy Recycling Oxidation System" which is a patented, closed thermal oxidation
process with no emissions vented into the atmosphere.
In addition to noting the type of technology offered, the report's assessment of BRI Energy
stated that "[a]lthough a pilot plant, which includes a gasifier and fermentation reactors, has been
performance tested under a Department of Energy grant, BRI Energy has not demonstrated that
tl:", teehnOln r,., haS bn"n 0—rated `N ah N4Q :�� is a feedstock Therefore the �eliabil:a..--.-:.-,.
'..bl .... t... Therefore ', n, iwiuvuuy o,. ....
criterion was not satisfied." Since the report was issued in September 2004, BRI may have
proceeded with testing with municipal solid waste. For some of those technologies that got past
initial screening and were evaluated, the same report had the following information:
4
Arrow Ecology & Engineering — ArrowBio Process - ArrowBio Process is a
patented, anaerobic digestion process that is intended for unsorted MSW. Has been
operating commercially in Tel Aviv, Israel since January 2003.
Canada Composting — BTA Process — BTA Process technology is a three -stage
anaerobic digestion process. Coupled with a MRE for waste pre-treatment and
separation. BTA technology is operating commercially in 26 facilities worldwide.
Waste Recovery Systems — Valorga Process — Valorga anaerobic digestion
technology operating commercially since 1988. Thirteen commercial facilities in Europe.
Masada Oxynol — CES Oxvnol Hydrolysis Process — proprietary CES Oxynol
Hydrolysis Process. Produces ethanol. Demonstrated at pilot project at Tennessee
Valley Authority's Muscle Shoals, Al facility. The first commercial plant for MSW is
currently under development in Middletown, NY. The plant has been permitted and is in
final stage of financing.
The above information which is only a sampling of the technologies listed in the study
show that "patented" technology or "patented" components of various alternative waste -to -
energy facilities appear to be the none rather than the exception. Using Mr. Jung's logic, since
most of these technologies hold patents, the County could determine any one of them to be
"unique." The problem is that it would be hard to argue that it was so "unique" that it was
"essential to the agency to accomplish its work" and is available from one supplier or source.
Since each of the above processes could achieve the same goal, the handling of our MSW, and
several of them also produce ethanol, any attempt to sole -source a contract with one vendor over
another would not survive a challenge.
The procurement code was adopted in the Special Session of 1993 through Act 8. In
Section I of the Act, it states that it is "the policy of the State to ensure the fair and equitable
treatment of all persons who deal with the procurement system of the State and counties.' It
goes on to say that no officer or employee "whose duties include purchasing shall use or attempt
tO ....z o official p.;o;t'.on to secure or grant unwarranted pr..;lege , exemptions, Or
advantages or exhibit any favoritism or prejudice to any prospective bidder or contractor. It is
the policy of the State to foster broad-based competition. Full and open competition shall be
encouraged."
Given the purpose of the procurement code and its clear preference for competition, a
purchasing agency bears a heavy burden to prove that a sole source contract is indeed required.
Among the reasons for enacting a procurement code is the protection of agencies from disruptive
litigation. The code provides for administrative appeals of agency decisions. Any attempt to
sole -source the waste -to -energy contract would almost certainly result in protests filed by other
providers. Investigations such as the one targeted at non-competitive contract awards at
Honolulu Airport show the risks entailed when agencies proceed to avoid going through normal
competitive contracting. The Director of the Hawaii Procurement Institute in testimony to State
legislators noted that "[t]he need to protect taxpayer dollars from potential abuse dictates that,
barring extraordinary and justifiable circumstances, no government agency should be exempt
from the Code's requirement to award contracts through fair and open competition." Hawaii
Procurement Institute— Opinion Number 2004-01. Since a cursory investigation into other
technologies demonstrates that other vendors hold patents and a number of them use a
combination of gasification and a secondary process to produce ethanol, BRI Energy could not
be categorized as a sole source.
Emergency Procurement
Section 103D-307 of the Hawaii Revised Statutes allows emergency purchase of goods
or services under certain conditions:
(a) The head o f a purchasing agency may obtain a good, service, or construction
essential to meet an emergency by means other than specified in this chapter when the following
circumstances exist:
(1) A situation of an unusual or compelling urgency creates a threat to
life, public health, welfare, or safety by reason of major natural disaster, epidemic, riot, fire, or
such other reason as may be determined by the head of that purchasing agency;
(2) The emergency condition generates an immediate and serious need
for goods, services, or construction that cannot be met through normal procurement methods and
the government would be seriously injured if the purchasing agency is not permitted to employ
the means it proposes to use to obtain the goods, services, or construction; and
functioning of government, the preservation or protection of irreplaceable property, or the health
and safety of any person will be seriously threatened.
(b) The emergency procurement shall be made with such competition as is
practicable under the circumstances and, where practicable, approval from the chief procurement
officer shall be obtained prior to procurement. A written basis for the emergency and for the
selection of the particular contractor shall be included in the contract file.
Under the rules adopted to govern emergency purchase, emergency purchases "may be
utilized to purchase only the immediate needs for the emergency and not subsequent non-
emergency requirements." HAR 3-122-88. The Hawaii Comity Department of Finance has also
adopted rules that govern emergency purchases. Under the department's rules, emergency
purchases "shall only be made if such purchases are required because of an urgent and
immediate need created by equipment or machinery breakdown, acts of public enemies, strikes,
natural disasters, civil disturbances, freight embargoes, fires, extraordinary weather, or by other
unforeseeable causes or circumstances over which the agencies have no control." Rule 16,
Section 16.3.
By definition, an emergency is an unforeseen or unexpected situation that requires an
immediate response. Some examples of emergencies would be hurricanes, tsunami, lava
inundation, and attacks from public enemies, strikes and earthquakes. Even in such a situation,
emergency procurement would only be allowed to address the immediate, urgent needs created
by the emergency. Emergency procurement should not be used to solve the long -tern problem
of disposing of solid waste.
The closure of the landfill is not a result of equipment or machinery breakdown. It is not
the result of the acts of public enemies. It is not the result of a strike or natural disaster, nor is it
the result of "unforeseen circumstances over which the agencies have no control." Instead, the
closure of the landfill is a "foreseen" circumstance. The closure of the landfill has been foreseen
for many years, and any intermediate problems of dealing with municipal solid waste currently
disposed of at the landfill can be addressed by trucking the trash to Pu'uanahulu, where the
County has a permitted landfill. The additional traffic generated by trucking the trash to
Pu'uanahulu could not be equated with emergencies such as earthquakes, hurricanes, or acts of
war. The presence on the island of a permitted, lined landfill where solid waste can be disposed
of undercuts any arguments that there is an immediate need to bypass the normal procurement
procedur„ s to pro:idc a 1^ 1 1—— ".._ r to the ala nds solid �.. ste d�spo�al col, ems.
Chapter 343 Environmental Impact Statements:
Chapter 343 of the Hawaii Revised Statutes requires that an environmental assessment
be made whenever an action proposes "the use of state or county lands or the use of state or
county funds." HRS Section 343-5. Since the site for the proposed waste -to -energy facility
7
would most probably be near our existing landfill on either land given to the County through
executive order or on State land, an EA would need to be done. An EA is a written evaluation to
determine whether an action may have a significant environmental impact. An environmental
impact means an effect of any kind, whether immediate or delayed, on any component of the
environment. HAR Section 11-200-2.
The EA would need to address such issues as flora and fauna, flooding and drainage, and
traffic impact on nearby residents. A proposing agency/individual would need to seek the input
of the County Planting Department regarding the general plan, consult with other agencies
having jurisdiction or expertise, and consult with citizen groups and individuals that may be
affected. The EA needs to identify potential impacts, evaluate the potential significance of each
impact, and provide for detailed study of significant impacts. The proposer would need to
prepare various public notices, provide for opportunities for public and agency comment,
respond to the comments and analyze alternatives in addition to the proposed action.
Significance criteria to be looked at include whether the action:
(1) involves an irrevocable commitment to loss or destruction of any natural or
cultural resource;
(2) curtails the range of beneficial uses of the environment;
(3) conflicts with the State's long-term environmental policies or goals and
guidelines as expressed in chapter 343, HRS, and any revisions thereof and amendments thereto,
court decisions, or executive orders;
(4) substantially affects the economic welfare, social welfare, and cultural
practices of the community or State;
facilities;
(5) substantially affects public health;
(6) involves secondary impacts, such as population changes or effects on pubic
(7) involves substantial degradation of environmental quality;
(8) is individually limited, but cumulatively has considerable effect on the
Pn�n mnm ant nr am,___ a co.n... ment for la;gC ..ct'.Cns'
(9) substantially affects a rare, threatened, or endangered species, or its habitat;
(10) detrimentally affects air or water quality or ambient noise levels,
(1 1) affects or is likely to suffer damage by being located in an environmentally
sensitive area such as a flood plain, tsunami zone, beach, erosion -prone area, geologically
hazardous land, estuary, fresh water, or coastal waters;
(12) substantially affects scenic vistas and viewplanes identified in county or state
plans or studies; or
(13) requires substantial energy consumption.
HAR Section 11-200-13.
Chapter 343 also requires that an EA be done when a "waste -to -energy" facility is
proposed. Given the fact that no prior facility like BRI Energy's has been permitted in the State
and that to date no commercial operation processing municipal solid waste using BRI's
technology exists anywhere in the world, significant attention and scientific review of the
technical aspects of the operation would probably be required by the State Department of Health.
In addition to all the issues regarding the flora and fauna and the commitment of the use of
government lands, issues regarding the safety of the gasifier, potential problems, disaster plans,
evacuation routes, emissions, transportation and storage of the ethanol would all need to be
addressed.
The purpose of an EA is to determine whether an EIS is required. Based upon the results
of the EA, an EIS might be required. Given the fact that the alternative technologies have not
been permitted yet in the State and in regards to BRI Energy, the fact that only a pilot project of
four tpd has been operating, the heat of the gasification chambers, the proximity to DHHL and its
residents, it would probably be faster to go straight to an EIS instead of facing potential litigation
over whether an EIS was required.
REQUEST FOR PROPOSAL
MEMORANDUM
BOBBIE JEAN LEITHEAD-TODD
DmF, KAETSU
BARBARA BELL
JAMES ARAKAKI
PETE HOFFMANN
DR. FRED HOLSCHUH
STAGY HIGA
August 2, zoos
Hilo, Hawaii
Prepared by:
Francis L. Jung, Esq.
Carol M. Jung, Esq.
JUNG & VASSAR, P.C.
A Law Corporation
75-170 Hualalai Road Suite D-114
Kailua-Kona, 111 96740
DONALD IKEDA
VIRGINIA ISBELL
ROBERT JACOBSON
ANGEL PILAGO
GARY SAFARIK
KOSTI SHIRVANIAN
GUYKANIHO
FRANCIS L JIJNG (NJ. DC & HI)
THOMAS N'. VASSAR (MD, VA. DC & HD
OSTIA KILPATRICK KOTNER(HL ORD
CAROL MONAHAN JUNG (HL Up
JUNG & VASSAR.) P.C.
ATTORNEYS AT LAw
A LAW CORPORATION
75-170 HuALALAI ROAD, SuITE 0.214
KAILUA-KONA, HI %740
(808) 326-4852
FAX (808) 326-7904
E-mail junglawegte.net
MEMORANDUM
TO: Bobby Jean Leithead-Todd, Esquire
Office of the Corporation Counsel
County of Hawaii
FROM: Francis L. Jung, Esq.
DATED: August 1, 2005
WASHINGTON D.C. OFFICT
P.O. BOX 12518
ARLINGTON. VA 2nIf2510
TEL 10J 4[42142
FAX 1034652146
vnur4wa16emW.mm
RE: The Necessity for Requests For Proposals ("RFP") for Solid Waste Disposal Contracts by
and between the County of Hawaii and Private Contractors
This Memorandum addresses the question of whether or not an RFP would be required,
prior to the execution of an agreement by and between the County of Hawaii and a private
corporation to build a facility that would convert solid waste to energy utilizing patented
technology. This question was raised during Pacific Waste's informational meeting with you, the
Mayor, and his staff earlier in July. Forptuops of legal analysis only, the facts surrounding
Pacific Waste and BRI's technology willl�iseddiscuss application of Hawaii law to the need
for RFPs in instances where: 1) patented technology is unavailable to parties other than patent
licensees, such as Pacific Waste and, 2) from a County perspective, emergency situations have
arisen. Under no circumstances is the following to be construed as a bid proposal of any kind
under Hawaii Law.
ISSUE:
Is the County of Hawaii required by law to issue a Request For Proposals ("RFP") for
purposes of contracting for the removal and disposal of solid waste from 1) existing landfills and
transfer stations and/or 2) the collection and disposal of solid waste by and between commercial
haulers and landfills and/or energy generating facilities?
Bobby Jean Leithead-Todd, Esquire
August 1, 2005
Page Two
ANSWER:
The Answer with respect to question 1 above is "not necessarily." With respect to
question 2 above, the answer is "no."
When contracting for the removal and disposal of solid waste from County landfills, as a
general rule, the County of Hawaii is required by law to issue an RFP in connection with the
solicitation of proposals for the "procurement or disposal of goods or services, or for
construction." HRS § 103D-104. There are, however, two primary exceptions to this
requirement: 1) when the specific need of the County can only be acquired from a sole source
(HRS § 10313-306); and 2) when an emergency situation requires the prompt
execution of a contract without an RFP (HRS § 10313-307). Consequently, where contracts
require the use of protected patented technology as an integral part of the services to be provided,
and/or where such services are sought in an emergency or crisis situation, no RFP would be
required.
With respect to item 2 above, no RFP is required where contracts are between private
solid waste disposal companies and commercial haulers so long as the County is not a party to
such agreement and the contract does not involve the "procurement or disposal of goods or
services, or for construction" by, or to, the County.
APPLICABLE LAW:
The following provisions of Chapter 103D of the Hawaii Revised Statutes are applicable
to the present situation. Particularly relevant provisions are highlighted for ease of reading.
§ 10313-102 Application of this chapter
(a) This chapter shall apply to all procurement contracts made by governmental bodies whether the
consideration for the contract is cash, revenues, realizations, receipts, or earnings, any of which the State receives or
is owed; in-kind benefits; or forbearance; provided that nothing in this chapter or rules adopted hereunder shall
prevent any governmental body from complying with the terms and conditions of any other grant, gift, bequest, or
cooperative agreement.
(b) Notwithstanding subsection (a), this chapter shall not apply to contracts by governmental bodies:
(1) Solicited or entered into before July I, 1994, unless the parties agree to its application to a contract
solicited or entered into prior to July I, 1994;
(2) To disburse funds, irrespective of their source:
Bobby Jean Leithead-Todd, Esquire
August I, 2005
Page Three
(A) For grants or subsidies as those terms are defined in section 4217-101, made by the State in accordance
with standards provided by law as required by article VII, section 4, of the State Constitution; or by the counties
pursuant to their respective charters or ordinances;
(B) To make payments to or on behalf of public officers and employees for salaries, fringe benefits,
professional fees, or reimbursements;
(C) To satisfy obligations that the State is required to pay by law, including paying fees, permanent
settlements, subsidies, or other claims, making refunds, and returning funds held by the State as trustee, custodian, or
bailee;
(D) For entitlement programs, including public assistance, unemployment, and workers' compensation
programs, established by state or federal law;
(E) For dues and fees of organizations of which the State or its officers and employees are members,
including the National Association of Governors, the National Association of State and County Governments, and
the Multi -State Tax Commission;
(F) For deposit, investment, or safekeeping, including expenses related to their deposit, investment, or
safekeeping;
(G) To governmental bodies of the State;
(H) As loans, under loan programs administered by a governmental body; and
(1) For contracts awarded in accordance with chapter 103F
(3) To procure goods, services, or construction from a governmental body other than the University of Hawaii
bookstores, from the federal government, or from another state or its political subdivision;
(4) To procure the following goods or services which are available from multiple sources but for which
procurement by competitive means is either not practicable or not advantageous to the State:
(A) Services of expert witnesses for potential and actual litigation of legal matters involving the State, its
agencies, and its officers and employees, including administrative quasi-judicial proceedings;
(13) Works of art for museum or public display;
(C) Research and reference materials including books, maps, periodicals, and pamphlets, which are
published in print, video, audio, magnetic, or electronic form;
(D) Meats and foodstuffs for the Kalaupapa settlement;
(E) Opponents for athletic contests;
(F) Utility services whose rates or prices are fixed by regulatory processes or agencies:
(G) Performances, including entertainment, speeches, and cultural and artistic presentations;
(H) Goods and services for commercial resale by the State;
(1) Services of printers, rating agencies, support facilities, fiscal and paying agents, and registrars for the
issuance and sale of the State's or counties' bonds;
Bobby Jean Leithead-Todd, Esquire
August 1, 2005
Page Four
(J) Services of attorneys employed or retained to advise, represent, or provide any other legal service to the
State or any of its agencies, on matters arising under laws of another state or foreign country, or in an action brought
in another state, federal, or foreign jurisdiction, when substantially all legal services are expected to be performed
outside this State;
(K) Financing agreements under chapter 37D; and
(L) Any other goods or services which the policy board determines by rules or the chief procurement officer
determines in writing is available from multiple sources but for which procurement by competitive means is either
not practicable or not advantageous to the State; and
(5) Which are specific procurements expressly exempt from any or all of the requirements of this chapter by:
(A) References in state or federal law to provisions of this chapter or a section of this chapter, or references
to a particular requirement of this chapter, and
(B) Trade agreements, including the Uruguay Round General Agreement on Tariffs and Trade (GATT)
which require certain non -construction and non -software development procurements by the comptroller to be
conducted in accordance with its terms.
(C) Unless other laws expressly exempt a governmental body from the requirements of this chapter or any
of its provisions, this chapter and all rules adopted by the policy board pursuant to section 103D-211 shall apply to
all governmental bodies of this State; except that any county may rely on other provisions established by charter,
ordinance, or rules adopted in accordance with chapter 91 provided that those provisions are consistent with the
requirements of this chapter.
§ 103D-104 Definitions
As used in this chapter, unless the context clearly requires otherwise:
"Business" means any corporation, partnership, individual, sole proprietorship, joint stock company, joint
venture, or any other private legal entity.
"Change order" means a written order signed by the procurement officer, directing the contractor to make
changes which the changes clause of the contract authorizes the procurement officer to order without the consent of
the contactor.
"Construction" means the process of building, altering, repairing, improving, or demolishing any public
structure or building, or other public improvements of any kind to any public real property. The term includes the
routine operation, routine repair, or routine maintenance of existing structures, buildings, or real property.
"Contact" means all types of agreements, regardless of what they may be called, for the procurement or
disposal of goods or services, or for construction.
"Contract modification" means any written alteration in specifications, delivery point, rate of delivery, period of
performance, price, quantity, or other provisions of any contract accomplished by mutual action of the parties to the
contract.
"Contractor" means any person having a contract with a governmental body.
"Cost -reimbursement contract" means a contract under which a contractor is reimbursed for costs which are
allowable and allocable in accordance with the contract terms and the provisions of this chapter, and a fee, if any.
Bobby Jean Leithead-Todd, Esquire
August 1, 2005
Page Five
"Data" means recorded information, regardless of form or characteristic.
"Employee" means an individual drawing a salary from a governmental body, whether elected or not, and any
noncompensated individual performing services for any governmental body.
"Established catalogue price" means the price included in a catalogue, price list, schedule, or other form that:
(1) Is regularly maintained by a manufacturer or contractor;
(2) Is either published or otherwise available for inspection by customers; and
(3) States prices at which sales are currently or were last made to a significant number of any category of
buyers or buyers constituting the general buying public for the goods or services involved.
"Goods" means all property, including but not limited to equipment, equipment leases, materials, supplies,
printing, insurance, and processes, including computer systems and software, excluding land or a permanent interest
in land, leases of real property, and office rentals.
"Governmental body" means any department, commission, council, board, bureau, authority, committee,
institution, legislative body, agency, government corporation, or other establishment or office of the executive,
legislative, or judicial branch of the State, including the office of Hawaiian affairs, and the several counties of the
State.
"Grant" means the furnishing of assistance, whether financial or otherwise, to any person to support a program
authorized by law. The term does not include an award whose primary purpose is to procure an end product, whether
in the form of goods, services, or construction; a contract resulting from such an award is not a grant but a
procurement contract.
"Invitation for bids" means all documents, whether attached or incorporated by reference, utilized for soliciting
bids.
"Policy board" means the procurement policy board created in section 10313-201.
"Procurement" means buying, purchasing, renting, leasing, or otherwise acquiring any good, service, or
construction. The term also includes all functions that pertain to the obtaining of any good, service, or construction,
including description of requirements, selection and solicitation of sources, preparation and award of contracts, and
all phases of contract administration.
"Procurement card" means a charge card, with predetermined limitations, used by government agencies in place
of cash or purchase orders for the purchase of goods, services, or construction.
"Procurement officer" means any person authorized to enter into and administer contracts and make written
determinations with respect thereto. The term also includes an authorized representative acting within the limits of
authority.
"Professional services" means those services within the scope of the practice of architecture, landscape
architecture, professional engineering, land surveying, real property appraisal, law, medicine, accounting, dentistry,
public finance bond underwriting, public finance bond investment banking, or any other practice defined as
professional by the laws of this State or the professional and scientific occupation series contained in the United
States Office of Personnel Management's Qualifications Standards Handbook.
Bobby Jean Leithead-Todd, Esquire
August 1, 2005
Page Six
"Purchase description" means the words used in a solicitation to describe the goods, services, or construction to
be purchased, and includes specifications attached to, or made a part of, the solicitation.
"Purchasing agency" means any governmental body which is authorized by this chapter or its implementing
rules and procedures, or by way of delegation, to enter into contracts for the procurement of goods, services, or
construction.
"Request for proposals" means all documents, whether attached or incorporated by reference, utilized for
soliciting proposals.
"Responsible bidder or offeror" means a person who has the capability in all respects to perform fully the
contract requirements, and the integrity and reliability which will assure good faith performance.
"Responsive bidder" means a person who has submitted a bid which conforms in all material respects to the
invitation for bids.
"Services" means the furnishing of labor, time, or effort by a contractor, not involving the delivery of a specific
end product other than reports which are merely incidental to the required performance.
"Specifications" means any description of the physical or functional characteristics, or of the nature of a good,
service. or construction item. The term includes descriptions of any requirement for inspecting, testing, or preparing
a good, service, or construction item for delivery.
"Using agency" means any governmental body which utilizes any goods, services, or construction procured
under this chapter.
§ 10313-301 Methods of source selection
Unless otherwise authorized by law, all contracts shall be awarded by competitive sealed bidding pursuant to
section 10313-302, except as provided in:
(1) Section 103D-303 (Competitive sealed proposals);
(2) Section 10313-304 (Professional services procurement);
(3) Section 103D-305 (Small purchases);
(4) Section 10313-306 (Sole source procurement); and
(5) Section 103D-307 (Emergency procurements).
§ 10313-306 Sole source procurement
(a) A contract may be awarded for goods, services, or construction without competition when the head of a
purchasing agency determines in writing that there is only one source for the required good, service, or construction,
the determination is reviewed and approved by the chief procurement officer, the written determination is posted in
the manner described in rules adopted by the policy board, and no objection is outstanding. The written
determination, any objection, and a written summary of the disposition of any objection shall be included in the
contract file.
Bobby Jean Leithead-Todd, Esquire
August 1, 2005
Page Seven
(b) The written determination shall contain such information as the rules of the policy board require. Persons
may file written objections to the issuance of a contract pursuant to this section. Rules of the policy board shall
provide for the disposition of objections, including a written summary of the disposition.
(c) The rules of the policy board shall include a non -exhaustive list of procurements which constitute sole source
procurements and criteria for determining when a particular procurement may be determined to be a sole source. The
rules shall also prescribe when cost or pricing data must be considered and how they are to be used in establishing
the price, terms, and conditions, if any, for a contract awarded pursuant to this section.
§ 10313307 Emergency procurements
(a) The head of a purchasing agency may obtain a good, service, or construction essential to meet an emergency
by means other than specified in this chapter when the following conditions exist
(1) A situation of an unusual or compelling urgency creates a threat to life, public health, welfare, or safety by
reason of major natural disaster, epidemic, riot, fire, or such other reason as may be determined by the head of that
purchasing agency;
(2) The emergency condition generates an immediate and serious need for goods, services, or construction that
cannot be met through normal procurement methods and the government would be seriously injured if the purchasing
agency is not permitted to employ the means it proposes to use to obtain the goods, services, or construction; and
(3) Without the needed good, service, or construction, the continued functioning of government, the
preservation or protection of irreplaceable property, or the health and safety of any person will be seriously
threatened.
(b) The emergency procurement shall be made with such competition as is practicable under the circumstances
and, where practicable, approval from the chief procurement officer shall be obtained prior to the procurement A
written determination of the basis for the emergency and for the selection of the particular contractor shall be
included in the contract file.
FACTS ASSUMED:
For purposes of this Memorandum, we have made the following assumptions of fact:
1. The Environmental Protection Agency ("EPA") is requiring that the Hilo
Landfill, presently being utilized to dispose of solid waste in East Hawaii, be closed by March
2006;
2. With the closure of the Hilo Landfill, there exists no facility in East Hawaii
legally capable of accepting East Hawaii's solid waste;
3,
Bobby Jean Leithead-Todd, Esquire
August 1, 2005
Page Eight
The County of Hawaii has not yet issued an RFP for development and
implementation of another East Hawaii Landfill; and
4. Unless a new East Hawaii Landfill is created and accepted by the EPA, or the
life of the present East Hawaii Landfill is extended, East Hawaii's currently generated solid
waste will require that said solid waste be transported to a West Hawaii Landfill for disposal.
LEGAL ASSERTIONS
1. Patented rights by their nature grant exclusive right to use the technology
patented to the patent owners See, e.g. U.S. Patent Abstracts 6,340,581 and 5,821,111 attached
hereto as Exhibits "I" and "2", providing patents for certain technology capable of converting
solid waste to ethanol and electricity while reducing the mass of solid waste generated for
disposal and the need to transport the same to other transfer stations and landfills; and
2. Patent holders or owners may license third parties to utilize such technology
exclusively. See also e.g. , Letter from Bill Bruce, President of BRI to Virginia Isbell dated July
28, 2005, affirming Pacific Waste's exclusive right to utilize BRI's patented technology in
Hawaii, attached as Exhibit "3."
DISCUSSION:
The South Hilo Landfill is located in Hilo and the United States Environmental
Protection Agency ("EPA"), for health and safety reasons, is requiring that this facility be
closed by March 2006. With the closure of Hilo's landfill, there will be no facility in East
Hawaii that will be able to accept East Hawaii's solid waste. At present, the County of Hawaii
does not have an RFP issued requesting bids for development of a solid waste landfill to be
located in East Hawaii or an RFP for transporting solid waste from East to West Hawaii. To
date, the County has contracted with a law firm located on the East Coast to draft an RFP. That
proposal will become due, however, well past the March 2006 deadline.
Bobby Jean Leithead-Todd, Esquire
August 1, 2005
Page Nine
An Emergency Situation
Under such circumstances, it would appear that the provisions of HRS § 103D-
307 apply if the "head of a purchasing agency" determines that,
(1) A situation of an unusual or compelling urgency creates a threat to life, public health, welfare, or safety by
reason of major natural disaster, epidemic, riot, fire, or such other reason as may be determined by the head of that
purchasing agency;
(2) The emergency condition generates an immediate and serious need for goods, services, or construction that
cannot be met through normal procurement methods and the government would be seriously injured if the purchasing
agency is not permitted to employ the means it proposes to use to obtain the goods, services, or construction; and
(3) Without the needed good, service, or construction, the continued functioning of government, the
preservation or protection of irreplaceable property, or the health and safety of any person will be seriously
threatened.
Under the present circumstances, viz. the EPA mandated closing of the Hilo
Landfill, the law would permit the head of the procuring County agency to determine that a
public health and safety emergency situation exists, and that under such circumstances, the need
for a timely and efficient remedy outweighs the need for delay inherent in the RFP process. This
could be effected if an emergency was declared by ordinance by the County Council pursuant to
the provisions of HRS §§ 91 F and 10313-102 ( c) cited above.
Sole Source
Additionally, using BRI as an example, where a company has developed patented
technology which efficiently and economically transforms solid waste to ethanol and electricity,
(see e.g., "A Report on a New Technology that addresses multiple Energy and Waste Disposal
solutions" attached as Exhibit "4"), the head of a procuring agency has the right to reject the use
of an RFP and offer a contract to a "sole source" if,
(a) A contract may be awarded for goods, services, or construction without competition when the head of a
purchasing agency determines in writing that there is only one source for the required good, service, or construction,
the determination is reviewed and approved by the chief procurement officer, the written determination is posted in
the manner described in rules adopted by the policy board, and no objection is outstanding. The written
determination, any objection, and a written summary of the disposition of any objection shall be included in the
contract file.
(b) The written determination shall contain such information as the rules of the policy board require. Persons
may file written objections to the issuance of a contract pursuant to this section. Rules of the policy board shall
provide for the disposition of objections, including a written summary of the disposition.
Bobby Jean Leithead-Todd, Esquire
August 1, 2005
Page Ten
(c) The rules of the policy board shall include a non -exhaustive list of procurements which constitute sole source
procurements and criteria for determining when a particular procurement may be determined to be a sole source. The
rules shall also prescribe when cost or pricing data must be considered and how they are to be used in establishing
the price, terms, and conditions, if any, for a contract awarded pursuant to this section.
Where patented technology is essential in providing a service to the County, in
BRI's case, the technology only works when a patented micro-organism capable of digesting
solid waste and converting said waste to ethanol is utilized. Using BRI as an example, BRI has
obtained patents for its technology. (See copies of the patent abstracts, attached hereto as
Exhibits "I" and "2.") BRI also has an Exclusive Agreement with Pacific Waste to market its
product in the State of Hawaii.. (See Letter From BRI to Virginia Isbell dated July 28, 2005, see
attached hereto as Exhibit "3.") Consequently, only BRI, its assignees and/or licensees can use
BRI's technology. As Pacific Waste has obtained the sole and exclusive right to utilize this
technology in Hawaii, it would appear that, for purposes of utilizing BRI's technology in Hawaii,
the provisions of HRS § 103D-306 are applicable and Pacific Waste is the "sole source" for such
technology.
Again, however, like the requirements of HRS § 10313-307 (emergency), HRS §
103D-306 also requires a determination by the "head of the purchasing agency" that the patented
technology meets the solid waste needs of the County of Hawaii and that the sole source from
which the patented technology can be obtained is the patented owner of the technology or its
exclusive assignee.
Contracts Between Non -Governmental Parties
There is no legal basis upon which to conclude that contracts between non-
governmental entities require the issuance of an RFP by the County of Hawaii. Consequently,
solid waste haulers are free to dispose of their solid waste to such private landfills or energy
producers as they wish.
We hope that the foregoing will provide some indication and assistance to
corporation counsel with respect to the need for RFPs in solving the solid waste problems
confronting the County of Hawaii. Should you have any questions concerning the foregoing,
please feel free to contact us at your convenience. Thank you for your consideration.
United States Patent 6,340,581
Gaddy January 22, 2002
Biological production of products from waste gases
Abstract
A method and apparatus are designed for converting waste gases from industrial
processes such as oil refining, and carbon black, coke, ammonia, and methanol
production, into useful products. The method includes introducing the waste gases into a
bioreactor where they are fermented to various products, such as organic acids, alcohols,
hydrogen, single cell protein, and salts of organic acids by anaerobic bacteria within the
bioreactor. These valuable end products are then recovered, separated and purified.
Inventors: Gaddy; James L. (Fayetteville, AR)
Assignee: Bioengineering Resources, Inc. (Fayetteville, AR)
Appl. No.: 219395
Filed: December 23, 1998
Current U.S. Class: 435/140; 435/163; 435/262.5; 435/266
Intern'l Class: C12P 007/54; C12P 007/08
Field of Search: 435/140 161 163 135 262 5 266
References Cited lReferenced By]
U.S. Patent Documents
4497637
Feb., 1985
Purdy et al.
48/111.
4515759
May., 1985
Burnes et al.
423/220.
4553981
Nov., 1985
Fuderer
48/62.
4568644
Feb., 1986
Wang et al.
435/161.
4652526
Mar., 1987
Hsu
435/253.
4692172
Sep., 1987
Stellaccio et al.
48/197.
4721676
Jan., 1988
Zeikus
435/253.
4732855
Mar., 1988
Zeikus et al.
435/141.
4771001
Sep., 1988
Bailey et al.
435/139.
4919813
Apr., 1990
Weaver
210/603.
4921799
May., 1990
Kitaura et al.
435/167.
4935360
Jun., 1990
Klemps et al.
435/140.
4994093
Feb., 1991
Wetzel et al.
48/197.
5026647
Jun., 1991
Tomes et al.
435/244.
5036005
Jul., 1991
Tedder
435/161.
5059288
Oct., 1991
Curry
203/43.
5077508
Dec., 1991
Sublette
435/168.
5110319
May., 1992
Turpin et al.
44/451.
5134944
Aug., 1992
Keller et al.
110/234.
5173429
Dec., 1992
Gaddy
435/163.
5238469
Aug., 1993
Briesacher et al.
95/115.
5593886
Jan., 1997
Gaddy.
5807722
Sep., 1998
Gaddy.
5821111
Oct., 1998
Gaddy.
Foreign
Patent Documents
282750
Oct., 1987
DE.
0282750 Sep., 1988 EP.
WO 98/00558 Jan., 1998 WO.
Other References
The Merck Index, 12th Editiion, items 7764, 1725, 1996.*
Gest, Howard and Kamen, Martin D., "Photoproduction of Molecular Hydrogen
by Rhodospirillum Rubrum." (Jun. 3, 1949) Science, vol. 109, p. 558-559.
Bott, Michael and Thaurer, Rudolf K., "Proton Translocation Coupled to the
Oxidation of Carbon Monoxide to CO.sub.2 and H.sub.2 in Methanosarcina
Barkeri." (1989) p. 469-472.
Dashekvicz, M.P., Uffen, R.L., "Identification of a Carbon Monoxide -
Metabolizing Bacterium as a Strain of Rhodopseudomonas Gelatinosa (Molish)
van Niel." (Apr. 1979) International Journal of Systematic Bacteriology, p. 145-
148.
Diekert, Gabriele and Ritter, Maria, "Carbon Monoxide Fixation into the
Carboxyl Group of Acetate During Growth of Agrobacterium Woodii on H.sub.2
and CO.sub.2. " (1983) FEBS Microbiology Letters 17, p. 299-302.
Fuller, R.C., "Photosynthetic Carbon Metabolism in the Green and Purple
Bacteria." (1978) Chapter 36, p. 691-705.
Goar, B. Gene, "Sulfinol Process Has Several Key Advantages." (Jun. 30, 1969)
The Oil and Gas Journal, p. 117-120.
Miller, Terry L. and Wolin, M.J., "Oxidation of Hydrogen and Reduction of
Methanol to Methane is the Sole Energy Source for a Methanogen Isolated from
Human Feces." (Feb. 1983) Journal of Bacteriology, p. 1051-1055.
O'Brien, Jill M., et al. "Association of Hydrogen Metabolism with Unitrophic or
Mixotrophic Growth of Mathanosarcina Barkeri on Carbon Monoxide." (Apr.
1984) Journal of Bacteriology, p. 373-375.
Rensfelt, Erik, et al., "Fuel Gas from Municipal Waste in an Integrated
Circulating Fluid -Bed Gasification/Gas-Cleaning Process." (1988).
Supperich, E. et al. "Carbon Monoxide Fixation into the Carboxyl Group of
Acetyl Coenzyme A During Autotrophic Growth of Methanobacterium." (Feb.
1983) FEBS Letters, vol. 152, No. 1, p. 21-23.
Uffen, R.L., et al. "Mutants of Rhodospirillum rubmm Obtained After Long -
Term Anaerobic Dark Growth." (Dec. 1971) Journal of Bacteriology, p. 1348-
1356.
Uffen, Robert L., "Anaerobic Growth of a Rhodoseudomonas Species in the
Dark With Carbon Monoxide as Sole Carbon and Energy Substrate." (Sep. 1976)
Proc. Natl. Acad. Sci. USA, vol. 73, No. 9, p. 3298-3302.
Vignais, Paulette M., et al., "Hydrogenase, Nitrogenase, and Hydrogen
Metabolism in the Photosynthetic Bacteria." (1985) Advances in Microbial
Physiology, vol. 26, p. 155-234.
Demain, et al. "Industrial Microbiology and Biotechnology." (1986) AJM, p.
332-335.
Crueger and Crueger, "Biotechnology: A Textbook of Industrial Microbiology."
2.sup.nd Ed., Sinauer Assoc., Inc., p. 74-89.
May, Patricia. 'Biotechnology Company Set For Fayetteville." (Oct. 29, 1992)
Springdale Morning News, p. IA.
"Industrial Innovations For Tomorrow, New Process Uses Bacteria To
Transform Waste Gases Into Useful Chemicals." (Aug. 1992) U.S. Dept. of
Energy Publication.
Morinaga, Tsuyoshi and Kawada, Naoki. "The Production of Acetic Acid From
Carbon Dioxiade and Hydrogen by an Anaerobic Bacterium." (1990) Journal of
Biotechnology, 14, p. 187-194.
Bank, S., et al., 'Biological Conversion of Coal Synthesis Gas to Methane."
(Sep. 1987) Energy Progess, vol. 7, No. 3, p. 157-160.
Zeikus, J.G. "Chemical and Fuel Production by Anaerobic Bacteria." (1980)
Annual Review Microbiology, p.423-464.
Alden, H., et al. "Energy from Biomass and Wastes." (Mar. 199 1) IGT.
Bouvier, J.M., et al. "Gas -Solid Pyrolysis of Tire Wastes --Kinetics and Material
Balances of Batch Pyrolysis of Used Types." (1987) Resources and
Conservation, vol. 15, p. 205-214.
Maynowski, C.W., et al. "Fermentation as an Advantageous Route for the
Production of an Acetate Salt for Roadway Deicing." (1985) American Chemical
Society, vol. 24, p. 457-465.
Eds by Clayton, R.K. and Sistrom, W.R. "Photosynthetic Carbon Metabolism in
the Green and Purple Bacteria, The Photosynthetic Bacteria." (1978) Plenum
Press, New York, p. 691-705.
Tracey, C.A. and Ashare, E. "Biomethanation of Biomass Pyrolysis Gases."
(Jun. 1981) Solar Energy Research Institute, p. 1-148.
Klasson, K. T., et al., "Bioconversion of Synthesis Gas into Liquid or Gaseous
Fuels." (Aug. 1992) Enzyme Microbiology Technology, vol. 14, p. 602-608.
Klemps, R., et al. "Production of Acetic Acid by Actogenium kivui." (1987)
Applied Microbiology and Technology, p. 229-234.
Waber, L.J. and Wood, H.G. "Mechanism of Acetate Synthesis from CO.sub.2
by Clostridium acidiurici." (Nov. 1979) Journal of Bacteriology, vol. 140, p.
468-478.
Vignais, P.M., et al. "Hydrogenase, Nitrogenase, and Hydrogen Metabolism in
the Photosynthetic Bacteria." (1985) Advances in Microbial Physiology, Vo. 26,
p. 163-177.
Gest, H. and Kamen, M.D. "Photoproduction of Molecular Hydrogen by
Rhodopirillum rubrum." (Jun. 3, 1949) Science, vol. 109, p. 558-559.
Kohimiller, E.F. Jr. and Gest, H. "Acids By Rhodospirillum rubrum." (Dec. 5,
1950) Dept. Of Microbiology, School of Medicine, Western Reserve University,
Cleveland, Ohio, vol. 61, p. 269-282.
Diekert, G. and Ritter, M. "Carbon Monoxide Fixation into the Carboxyl Group
of Acetate During Growth of Acetobacterium woodii on H.sub.2 and CO.sub.2."
(1983) Federation of European Microbiological Societies, Microbiology Letters
17, p. 299-302.
Wiegel, Jurgen, et al. "Isolation from Soil and Properties of the Extreme
Thermophile Clostridium thermohydrosul furi cum." (Sep. 1979) Journal of
Bacteriology, p. 800-810.
Wardell, James M. and King, C. Judson. "Solvent Equilibra for Extraction of
Carboxylic Acids from Water." (1978) Journal of Chemical and Engineering
Data, vol. 23, No. 2, p. 144-148.
Helsel, R.W. 'Removing Carboxylic Acids from Aqueous Wastes, CEP." (May
1977) Hydroscience Environmental Systems.
Leigh, J.A. et al. "Acetogenium Kiwi, A New Thermophilic Hydrogen -
Oxidizing, Acetogenic Bacterium." Arch. Microbiol. 129, 275-280.
Moller, et al. "Sporomusa, A New Genus of Gram -Negative Anaerobic Bacteria
Including Sporomusa Sphaeroides Spec. Nov. And Sporomusa Ovata Spec.
Nov." (1984) Arch Microbiology 139: 388-390.
Balch, et al. "Acetobacterium, A New Genus of Hydrogen -Oxidizing, Carbon
Dioxide -Reducing, Anaerobic Bacteria." (Oct. 1977) Journal of Systematic
Bacteriology, p. 355-361.
Lorowitz, William H. and Bryant, Marvin P. "Peptostreptococcus Productus
Strain That grows Rapidly with CO as the Energy Source." (May 1984) Applied
and Environmental Microbiology, p. 70-74.
Genther, B.R. Sharak and Bryant, M.P. "Growth of Eubacterium Limosum with
Carbon Monoxide as the Energy Source." (Jan. 1982) Applied and
Environmental Microbiology, p. 70-74.
Kerby, Lee Lynd R. and Zeikus, J.G. "Carbon Monooxide Metabolism of the
Methylotrophic Acidogen Butyribacterium Methylotrophicum." (Jan. 1982)
Journal of Bacteriology, p. 255-263.
Gottschalk, Gerhard and Braun Manfred. 'Revival of Name Clostridium
Aceticum." (Oct. 1981) International Journal of Systematic Bacteriology, p. 476.
Ohwaki, Kyoko and Hungate, R.E. "Hydrogen Utilization By Clostridia in
Sewage Sludge." (Jun. 1977) Applied and Environmental Microbiology, p. 1270-
1274.
Kerbv, R., et al. "Single -Carbon Catabolism in Acetogens: Analysis of Carbon
Flow in Acetobacterium woodii and Butyribacterium Methylotrophicum by
Fermentation and 13 C Nuclear Magnetic Resonance Measurement." (Sep. 1983)
Journal of Bacteriology, p. 1208-1218.
Sugaya, K. et al. "Production of Acetic Acid by Clostridium Thermoaceticum in
Batch and Continuous Fermentation." (1986) Biotechnology and Bioengineering,
vol. XXVIII, p. 678-683.
Schwartz, Robert D. and Keller, Frederick A. Jr. "Isolation of a Strain of
Clostridium Thermoaceticum Capable of Growth and Acetic Acid Production at
pH 4.5." (Jan. 1982) Applied and Environmental Microbiology, p. 117-123.
Schwartz, Robert D. and Keller, Frederick A. Jr. "Acetic Acid Production By
Clostridium Thermoaceticum in pH -Controlled Batch Fermentations at Acidic
pH." (Jan. 1982) Applied and Environmental Microbiology, p. 1385-1392.
Daniel, Steven L., et al. "Characterization of the H.sub.2 - and CO -Dependent
Chemolithotrophic Potentials of the Acetogens Clostridium Thermoaceticum and
Acetogenium Kivui." (Aug. 1990) Journal of Bacteriology, p. 4464-4471.
Rothstein, David M. "Clostridium Thermosaccarolyticum Strain Deficient in
Acetate Production." (Jan. 1986) Journal of Bacteriology, p. 319-320.
"Nickel Transport by the Thermophilic Acetogen Acetogenium Kivui." (May
1989) Applied and Environmental Microbiology, p. 1078-1081.
Yang, Hsuichin and Drake, Harold L. "Differential Effects of Sodium on
Hydrogen- and Glucose- Dependent Growth of the Acetogenic Bacterium
Acetogenium Kivui." Applied and Environmental Microbiology, p. 81-86.
Sanchez-Riera, F., et al. "Influence of Environmental Factors in the Production
of R(-)-1,2-Propanediol by Clostridium Thermosaccharolyticum." Biotechnology
Letters, vol. 9, No. 7, 449 et seq.
Bhatnagar, L. et al. "Analysis of Hydrogen Metabolism in Methanosarcina
Barkeri: Regulation of Hydrogenase and Role of CO -Dehydrogenase in H.sub.2
Production." (1987) Federation of European and Microbiological Societies,
Microbiology Letters 41, p. 337-343.
Dashekvicz, M.P. and Uffen, R.L. "Identification of a Carbon Monoxide -
Metabolizing Bacterium as a Strain of Rhodoseudomonas Gelantinosa (Molish)
Van Niel." (Apr. 1979) International Journal of Systematic Bacteriology, vol. 29,
p. 145-148.
Uffen, R.L., et al. "Mutants of Rhodospirillum Rubrum Obtained After Long -
Term Anaerobic, Dark Growth." (Dec. 1973) Journal of Bacteriology, vol. 108,
No. 3, p.1348-1356.
Thauer, R.K. et al. "The Active Species on CO2 Utilized By Reduced
Ferredoxin: CO.sub.2 Oxidoreductase from Clostridium Pasteurianum." (1975)
European Journal of Biochemistry, 55, 111-117.
Barik, S., et al. "Biological Production of Alcohols from Coal Through Indirect
Liquefaction." (1988) The Humana Press, p. 363-378.
Klasson, K.T., et al. "Biological Production of Liquid and Gaseous Fuels from
Synthesis Gas." (1990) Applied Biochemistry and Biotechnology, vol. 24/25.
Vega, J.L., et al. "The Biological Production of Ethanol from Synthesis Gas."
(1989) Applied Biochemistry and Biotechnology, vol. 20/21.
Martin, D.R. et al. "Carbon Monoxide -Dependent Evolution of Hydrogen by the
Homoacetate-Fermenting Bacterium Clostridium Thermoaceticum." (1983)
Current Microbiology, vol. 8, p. 337-340.
O'Brien, J.M., et al. "Association of Hydrogen Metabolism with Unitrophic or
Mixotrophic Growth of Methanosarcina Barkeri on Carbon Monoxide." (Apr.
1984) Journal of Bacteriology, vol. 158, No. 1, p. 373-375.
Uffen, R.L. "Anaerobic Growth of a Rhodopseudomonas Species in the Dark
with Carbon Monoxide as Sole Carbon and Energy Substrate." (Sep. 1976)
Microbiology, vol. 73, No. 9, p. 3298-3302.
Goar, B.G. "Sulfinol Process has Several Key Advantages." (Jun. 30, 1969) The
Oil and Gas Journal, p. 117-120.
Stupporich, E., et al. "Carbon Monoxide Fixation into the Carboxyl Group of
Acetyl Coenzyme A During Autotrophic Growth of Methanobacterium." (Feb.
1983) Federation of European Biochemical Societies, Microbiology Letters, vol.
152, No. 1, p. 21-23.
Bott, M. and Thauer, R.K. "Proton Translocation Coupled to the Oxidation of
Carbon Monoxide to CO.sub.2, and H.sub.2 in Methanosarcina Barkeri." (1989)
European Journal of Biochemistry, p. 469-472.
Anderson, L. and Fuller, R.C. 'Photosynthesis in Rhodospirillum Rubrum I.
Autotrophic Carbon Dioxide Fixation." (1967) Plant Physiology, p. 487-490.
Barik, S., et al. 'Biological Upgrading of Coal -Derived Synthesis Gas: Final
Report (Abstract)." (1989) Fossil Fuels, vol. 110, p. 201.
Kawakami, S., et al. 'Pyrolysis Process for Scrap Tires." (1980) American
Chemical Society Symposium Series, 130, Washington, D.C.
Rensfelt, E. and Ekstrom, C. 'Biomass and Wastes." (1991)Inst. Gas Tech.
Zeikus, J.G. "Chemical and Fuel Production by Anaerobic Bacteria." (1980)
Annual Review of Microbiology, p. 423-464.
Lundback, K.M.O., et al. 'Parameters Affecting the Kinetics of Ethanol
Production from CO, CO.sub.2, and H.sub.2 by clostridium Ijungdahlii." (May
1990) Presented at Twelfth Symposium on Biotechnology for Fuels and
Chemicals, Gatlinsburg, Tennesse.
Tanner, R.S. and Yang, D. "Clostridium ljungdahlii PETC Sp. Nov. A New
Acetogenic, Gram -Positive, Anaerobic Bacterium." (1990) Abstracts of the 1990
Annual Meeting of the American Society for Microbiology, No. R-21, p. 249.
Gaddy. "Indirect Coal Liquification." (1985) Technical Report.
Vega, J.L. et al. "Study of Gaseous Substrate Fermentations: Carbon Monoxide
Conversion to Acetate. 2. Continuous Culture." (Sep. 1989) Biotechnology and
Bioengineering, vol. 34, p. 785-793.
Nakamura, et al. "Taxonomic Study of Bacillus Coagulans Hammer 1915 with a
Proposal for Bacillus Smithii sp. Nov." (Jan. 1988) International Journal of
Systematic Bacteriology, vol. 38, p. 63-73.
Krueger, et al. "Thermophilic Bacilli Growing with Carbon Monoxide." (Nov.
1984) Archives of Microbiology. vol. 139, No. 4, p. 402-408.
Arora, D., et al. 'Production of Ethanol from Refinery Waste Gases, Phase II --
Technology Development." (Jul., 1985) Annual Report, in Energy Conservation,
p. 1-56.
Arora, D., et al. 'Production of Ethanol from Refinery Waste Gases, Phase III --
Engineering Development." (Nov. 1996) Annual Report, in Energy
Conservation, p. 1-23.
Arora, D., et al. 'Production of Ethanol from Refinery Waste Gases, Phase,",
(Aug. 1997) Final Report, in Energy Conservation, pp. 1-96.
DOE Report, "High Pressure Synthesis Gas Conversion: Task 3: High Pressure
Profiles," DOE/PC/91028-T6; Order No. DE93040517, 53 pages Available:
NTIS from: Energy Research Abstracts, 18(11), Abstract No. 32677 (1993).
Chemical Abstracts, 123(1), Columbus, Ohio, Abstract No. 7982, Jul. 3, 1995,
"High Pressure Synthesis Gas Conversion: Task 3: High Pressure Profiles,"
XP002117033.
DOE Report, 'Biological Production of Ethanol from Coal: Tasks 4 Report,
Continuous Reactor Studies," DOE/PC/89876-T17; Order No. DE93009047, 176
pages Available: NTIS from: Energy Research Abstracts, 18(5), Abstract No.
11669 (1993).
Chemical Abstracts, 120(22), Columbus, Ohio, Abstract No. 275289, May 30,
1994, 'Biological Production of Ethanol from Coal: Task 4 Report, Continuous
Reactor Studies," XP002117034.
DOE Report, "High Pressure Synthesis Gas Fermentation," DOE/PC/91028-T5;
Order No. DE92019656, 21 pages Available: NTIS from: Energy Research
Abstracts, 17(12), Abstract No. 33274 (1992).
Chemical Abstracts, 119(7), Columbus, Ohio, Abstract No. 269118, Dec. 20,
1993, "High Pressure Synthesis Gas Fermentation," XP002117035.
R.S. Tanner et al., "Clostridium ljungdahlii sp. nov., an Acetogenic Species in
Clostridial rRNA Homology Group I," Int. J. Syst. Bacteriol., 43(2): 232-236
(Apr. 1993).
K. T. Masson et al., "Bioliquefaction of Coal Synthesis Gas," Am. Chem. Soc.,
Div. Fuel Chem., 37(4): 1977-1982 (1992).
B. B. Elmore, 'Biological Production of Ethanol from Coal Synthesis Gas using
Clostridium Ljungdahlii, Strain PETC", Univ. Microfilms Int., Order No,.
DA9111206 from: Diss. Abstr. Int. B 1991, 51(11), 5459 (1990).
Chemical Abstracts, 115(9), Columbus, Ohio, Abstract No. 90621, Sep. 2, 1991,
XP002117038: B. B. Elmore, 'Biological Production of Ethanol from Coal
Synthesis Gas using Clostridium Ijungdahlii, Strain PETC'.
Primary Examiner: Marx; Irene
Attorney, Agent or Firm: Howson & Howson
Goverment Interests
This invention was supported by the U.S. Department of Energy, Grant Nos. DE-FCO2-
90CE40939 and DE-FC04-94AL98770. The U.S. Government has certain rights in this
invention.
Parent Case Text
This is a continuation of International Patent Application No. PCT/US96/11146, filed Jul.
1, 1996, and a continuation -in -part of U.S. patent application Ser. No. 08/674,417, filed
Jul. 1, 1996, now U.S. Pat. No. 6,136,577 which is a continuation -in -part of U.S. patent
application Ser. No. 08/347,512, filed Nov. 30, 1994, issued as U.S. Pat. No. 5,807,722,
which is a continuation application of U.S. patent application Ser. No. 08/258,446, filed
Jun. 10, 1994, issued as U.S. Pat. No. 5,593,886, which is a divisional application of U.S.
patent application Ser. No. 07/968,857, filed Oct. 30, 1992, now abandoned. This
application is also a continuation -in -part of U.S. patent application Ser. No. 08/808,088,
filed Feb. 28, 1997, issued as U.S. Pat. No. 5,821,111, which is a continuation of U.S.
patent application Ser. No. 07/220,686, filed Mar. 31, 1994, now abandoned.
Claims
What is claimed is:
1. A process for producing acetic acid comprising the steps of
(a) providing a continuous flow of an oxygen -free gas substrate selected from the group
consisting of.
(i) a gas substrate comprising carbon monoxide,
(ii) a gas substrate comprising carbon monoxide and hydrogen, and
(iii) a gas substrate comprising hydrogen and carbon dioxide into a fermentation reactor;
said fermentation reactor containing an aqueous nutrient medium and an anaerobic
acetogenic C. Ijungdahlii bacterium;
(b) directing a continuous flow of said liquid nutrient medium into said fermentation
reactor;
(c) fermenting said nutrient medium, and said gas using said bacterium at a pH in said
fermentation reactor of less than about 5.1;
wherein at least 2 g/L of said acetic acid is produced in free acid form in said
fermentation reactor in a broth;
(d) continuously removing a portion of said broth containing acetic acid from said
fermentation reactor; and
(e) recovering the acetic acid therefrom by contacting said removed broth containing the
product with a water -immiscible solvent having an affinity for said acetic acid and
optionally distilling said acetic acid from said water -immiscible solvent.
2. The process according to claim 1 wherein said gas is generated by an industrial process
selected from the group consisting of the manufacture of carbon black, ammonia, the
production of methanol, the production of coke, and the refining of petroleum.
3. The process according to claim 1 wherein said fermentation reactor is selected from
the group consisting of continuously stirred tank reactor, an immobilized microbial cell
bioreactor, a trickle bed bioreactor, a bubble column bioreactor, and a gas lift bioreactor.
4. The process according to claim 1 wherein said fermentation reactor is maintained at a
pressure of greater than one atmosphere.
5. The process according to claim 1 wherein said recovery step comprises separating said
acetic acid and said bacterium by passing said removed broth containing acetic acid
through a cell separation unit, returning said bacterium to the fermentation reactor to
maintain a high bacterial concentration and producing a bacterium -free, acetic acid -
containing stream.
6. The process according to claim 5 wherein said separating is accomplished by a step
selected from the group consisting of centrifugation, hollow fiber membrane filtration,
settling and ultrafiltration.
7. The process according to claim 1 wherein the process is conducted in the absence of
cell separation from said broth.
8. The process according to claim 1 wherein said recovery of acetic acid is accomplished
by (a) contacting said broth containing the acetic acid with a water -immiscible solvent
having a high affinity for the acetic acid in a countertlow mixing vessel and then (b)
optionally distillating the acetic acid of (a) to recover said water -immiscible solvent and
acetic acid.
9. The process according to claim 1 wherein said recovery of acetic acid is accomplished
by distillation.
10. The process according to claim 1 wherein said anaerobic acetogenic Clostridium
ljungdahlii bacterium is PETC.
11. The process according to claim 1 wherein said anaerobic acetogenic C. Ijungdahlii
bacterium is C. ljungdahlii ERI -2.
12. The process according to claim 1 wherein said fermentation reactor further contains
another anaerobic acetogenic bacterium selected from the group consisting of
Acetobacterium kiwi, A. woodii, Butyribacterium methylotrophicum, Clostridium
aceticum, C. acetobutylicium, C. formoacetium, C. kluyveri, C. thermoaceticum, C.
thermocellum, C. thermohydrosulfuricum, C. thermosaccharolyticum, Eubacterium
limosum, Peptostreptococcus productus, Rhodospiorillum rubrum and
Rhodopseudomonas gelatinosa.
13. The process according to claim 1 wherein said gas substrate (i) or (ii) further contains
carbon dioxide.
14. The process according to claim 13, wherein said gas substrate further contains a
component selected from the group consisting of nitrogen and methane.
15. The process according to claim 1, wherein the pH in the fermentation reactor is about
4.9.
16. The process according to claim 1 wherein said process was performed at greater than
15 atmospheres of pressure.
17. The process according to claim 1 wherein said fermentation reactor further contains a
surfactant which increases the consumption of carbon monoxide by said bacterium.
18. The process according to claim 1 wherein said gas substrate further comprises one or
more of nitrogen and methane.
19. The process according to claim 1, wherein after said recovery step, the acetic acid is
contacted with dolomitic lime and magnesium oxide and dried, thereby producing
calcium magnesium acetate.
20. The process according to claim 1, wherein after said recovery step, the acetic acid is
contacted with caustic potash and dried, thereby producing potassium acetate.
Description
FIELD OF THE INVENTION
The present invention is directed to biologic methods, processes, microorganisms, and
apparatus for producing products, materials, intermediates, and the like such as organic
acids, single cell protein ("SCP"), hydrogen, alcohols, and organic acid salts from the
waste gas streams of certain industrial processes and more particularly concerns a
process utilizing continuous gaseous substrate fermentation under anaerobic conditions to
accomplish this conversion.
BACKGROUND OF THE INVENTION
The conventional procedure for producing organic acids, alcohols, hydrogen and organic
acid salts is chemical synthesis of petroleum -derived feedstocks. The rapidly escalating
cost of petroleum has generated considerable interest in producing these valuable
commodities by fermentative processes that utilize renewable or waste materials as the
feedstock. Single cell protein is produced as a by-product of the fermentations, and is
generally used as an animal feed supplement.
There is also growing concern over the massive amounts of atmospheric pollutants and
greenhouse gases produced by conventional industrial processes. The Environmental
Protection Agency recently estimated that over six million metric tons of carbon
monoxide and nearly four million metric tons of hydrogen were discharged annually by
the industrial complex. A substantial portion of this waste carbon monoxide and
hydrogen is the result of carbon black manufacture and coke production, roughly 2.6
million metric tons of carbon monoxide and 0.5 million metric tons of hydrogen. Large
amounts of carbon monoxide or hydrogen are also produced by the ammonia industry
(125,144 metric tons of carbon monoxide in 1991), petroleum refining (8 metric tons per
thousand barrels), steel mills (152 pounds per metric ton of steel produced), and sulfate
pulping of wood (286 pounds per ton of pulp). In 1991, the adipic acid industry generated
40,773 metric tons of carbon monoxide that was burned for fuel value or flared. In many
cases, these gases are discharged directly to the atmosphere, placing a heavy pollution
burden on the environment.
Typically, the waste gases from the manufacture of industrial products are released at
low pressures and temperatures. Current technology cannot utilize these dilute gases
under such conditions. Adapting existing technology to separate and recover hydrogen or
carbon monoxide from these waste streams would be expensive and impractical.
In light of the foregoing, there exist needs in the art for cost effective and practical
methods, microorganisms, and apparatus for utilizing the above-described waste gases
and for producing products, materials, intermediates and the like such as organic acids,
alcohols, hydrogen and organic acid salts by other than chemical synthesis of petroleum
derived feedstocks.
SUMMARY OF THE INVENTION
In accordance with the present invention, products, materials, intermediates, and the like
such as organic acids, alcohols, hydrogen, single cell protein and/or organic acid salts are
produced from the waste carbon monoxide, hydrogen, and/or carbon dioxide of industrial
processes, thereby reducing environmental pollution while at the same time saving
energy and chemical feedstocks.
In accordance with an exemplary process of the present invention, the desired
components of the dilute gas mixtures are introduced into a bioreactor containing one or
more cultured strains of anaerobic bacteria that utilize the waste gas components by a
direct pathway to produce a desired compound. The compound is recovered from the
aqueous phase in a separate vessel or vessels, utilizing a suitable recovery process for the
compound produced. Examples of recovery processes include extraction, distillation or
combinations thereof, or other efficient recovery processes. The bacteria are removed
from the aqueous phase and recycled to avoid toxicity and maintain high cell
concentrations, thus maximizing reaction rates. Cell separation, if desired, is
accomplished by centrifugation, membranous ultrafiltration, or other techniques.
The principal object of the present invention is the provision of a process and/or
microorganism for the production of products, intermediates, materials, and the like such
as organic acids, hydrogen, single cell protein, alcohols, and/or organic acid salts from
carbon monoxide, hydrogen, and/or carbon dioxide.
Another object of the present invention is the provision of methods, microorganisms and
apparatus for the production of items such as organic acids, alcohols, hydrogen, single
cell protein and/or salts from the waste gas streams of industrial processes such as oil
refining, and production methods for generating carbon black, coke, ammonia, and
methanol.
A still further object of the present invention is the provision of a process for producing
acetic acid and/or ethanol from a waste gas stream of identical composition to that found
in the manufacture of carbon black.
Yet another and more particular object of the present invention is the provision of a
method, microorganism and apparatus involving continuous gaseous substrate
fermentation under anaerobic conditions to accomplish the conversion of waste gas
streams of certain industrial processes into useful products such as organic acids
including acetic acid, alcohols, hydrogen, single cell protein and organic acid salts.
Other objects and further scope of the applicability of the present invention will become
apparent from the detailed description to follow, taken in conjunction with the
accompanying drawings wherein like parts are designated by like reference numerals.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. I is a schematic diagram of a process of this invention for the production of acetic
acid from waste gas.
FIG. 2 is a schematic diagram of a process of this invention for the production of calcium
magnesium acetate salt (CMA) from waste gas.
FIG. 3 is a schematic diagram of a process of this invention for the production of ethanol
from waste gas.
FIG. 4 is a schematic representation of a continuous fermentation system in accordance
with an embodiment of the present invention.
FIG. 5 is a graphical illustration of the increase in cell concentration measured in optical
density at 580 nm (OD580) over time according to a method of this invention.
FIG. 6 is a graphical representation of an increase in acetic acid (IAC) produced by a
method of this invention over time.
DETAILED DESCRIPTION OF THE INVENTION
The term "waste gas" or "waste gas streams" as used herein means carbon monoxide and
hydrogen mixed with other elements or compounds, including carbon dioxide, nitrogen
and methane, in a gaseous state, which gases or streams are typically released or
exhausted to the atmosphere either directly or through combustion. Normally, release
takes place under standard smokestack temperatures and pressures. Accordingly, the
processes of the present invention are suitable for converting these atmospheric
pollutants into useful products such as organic acids, alcohols and organic acid salts.
These products include, but are not limited to acetic, propionic, and butyric acids;
methanol, ethanol, propanol, and n -butanol; plus salts, such as calcium magnesium
acetate (CMA) and potassium acetate (KA).
Anaerobic bacteria which are know to convert carbon monoxide and water or hydrogen
and carbon dioxide into alcohols and acids and acid salts include Acetobacterium kiwi,
A. woodii, Clostridium aceticum, Butyribacterium, methylotrophicum, C.
acetobutylicum, C. formoaceticum, C. kluyveri, C. thermoaceticum, C. thermocellum, C.
thermohydrosul furi cum, C. thermosaccharolyticum, Eubacterium limosum, C. Ijungdahlii
PETC and Peptostreptococcus productus. Anaerobic bacteria known to produce hydrogen
from carbon monoxide and water include Rhodospirillum rubrum and
Rhodopseudomonas gelatinosa.
More specifically, bacterial species such as Acetogenium kivui, Peptostreptococcus
productus, Acetobacterium woodii, Clostridium thermoaceticum and Eubacterium
Iimosum, produce acetate by the reaction:
4CO+2H.sub.2 0--CH.sub.3 COOH+2CO.sub.2 dG=-39 kcal/reac. (1)
Many anaerobic bacteria are also known to produce acetic acid from hydrogen and
carbon dioxide. These bacterial isolates include A. kivui, P. productus, and
Acetobacterium sp., which utilize homoacetic fermentation by anaerobically oxidizing
hydrogen and carbon dioxide according to the equation:
4H.sub.2 +2CO.sub.2--CH.sub.3 COOH+2H.sub.2 dG=-25 kJ/reac. (2)
Acetobacterium woodii and Acetoanaerobium noterae produce acetate from hydrogen
and carbon dioxide according to the above reaction, but in addition to acetate, A. noterae
produces some propionate and butyrate. Another chemolithotrophic bacterium,
Clostridium aceticum, produces acetate from carbon dioxide using a glycine
decarboxylase pathway.
Some bacteria, like A. kivui, P. productus, and A. woodii, produce acetate from either
carbon monoxide and water, or hydrogen and carbon dioxide. P. productus gives
particularly fast rates of conversion and demonstrates high tolerance to carbon monoxide;
however, this organism shows a preference to follow Equation (1) over Equation (2).
In addition to these listed bacteria, two strains of an additional clostridia which produce
acetic acid or ethanol from carbon monoxide and water, or hydrogen and carbon dioxide
have been isolated. One is Clostridium ljungdahlii ERI2, a rod -shaped, gram positive,
non -thermophilic anaerobe which gives superior acetic acid yields and operates at a low
pH, a characteristic which greatly enhances the recovery of the product. C. ljungdahlii
ERI2 carries out a vigorous acetogenic fermentation of glucose. It also infrequently
forms spores and carries out a primarily acetogenic fermentation of hexose or H.sub.2
:CO.sub.2. It is motile with peritrichous flagellation. This new strain of C. ljungdahlii,
referred to as ERI2, was isolated from a natural water source and was deposited with The
American Type Culture Collection, 10801 University Boulevard, Manassas, Va. on Dec.
8, 1992, under Accession No. 55380. The deposit was made freely available to the public
on Nov. 6, 1997.
In preparing the products of the present invention, "mixed strains" of the bacteria
enumerated hereinabove may be utilized. By mixed strains, it is meant a mixed culture of
two or more anaerobic bacteria. This mixed strain, when utilized in the process described
herein, produces organic acids (such as acetic acid and the like) or salts thereof, alcohols,
hydrogen, single cell protein, etc.
In the development of the present invention, new strains of anaerobic bacteria have been
isolated which enact this conversion with high efficiency. In addition, modifications to
the fermentation conditions can result in the production of ethanol instead of acetic acid
in some strains. Depending on the specific microorganism(s) utilized, variables which
must be considered in forming products from waste gases include nutrient constituents
and concentrations, medium, pressure, temperature, gas flow rate, liquid flow rate,
reaction pH, agitation rate (if utilizing a Continuously Stirred Tank Reactor), inoculum
level, maximum substrate (introduced gas) concentrations to avoid inhibition, and
maximum product concentrations to avoid inhibition.
In accordance with an exemplary embodiment of the present invention and as shown in
FIG. 1, a first step in the conversion process is the preparation of nutrient media (10) for
the anaerobic bacteria. The content of the nutrient media will vary based on the type of
anaerobe utilized and the desired product. The nutrients are constantly fed to a bioreactor
or fermenter (12), consisting of one or more vessels and/or towers of a type which
includes the Continuously Stirred Reactor (CSTR), Immobilized Cell Reactor (ICR),
Trickle Bed Reactor (TBR), Bubble column, Gas Lift Fermenters, or other suitable
fermentation reactor. Within the bioreactor (12) resides the culture, either single or mixed
species, of anaerobic bacteria utilized in the gas conversion process. For the CSTRs,
TBRs, Bubble Columns and Gas Lift Fermenters, these bacteria live dispersed
throughout the liquid phase of the reactor, but for ICRs, the bacteria adhere to an internal
packing medium. This packing medium must provide maximal surface area, high mass
transfer rate, low pressure drop, even gas and liquid distribution, and must minimize
plugging, fouling, nesting and wall channeling. Examples of such medium materials are
ceramic Berl saddles, Raschig rings or other high performance packings.
The waste gases (14) are continuously introduced into the bioreactor (12). The gas is
retained in the bioreactor (12) for the period of time which maximizes efficiency of the
process. Exhaust gases (16), containing inert substances and unreacted substrate gases,
are then released. The liquid effluent (18) is passed to a centrifuge, hollow fiber
membrane, or other filtration device (20) to separate out microorganisms that are
entrained. These microorganisms (22) are returned to the bioreactor (12) to maintain a
high cell concentration which yields a faster reaction rate (cell recycle).
A next step in the process is separation of the desired biologically produced product(s)
from the permeate or centrifugate (24). In the embodiment depicted in FIG. 1, the
permeate or centrifugate (24) is passed to an extraction chamber (26) where it is
contacted with a solvent (28). The solvent (28) should have a high distribution coefficient
for the desired end product, a high recovery factor, low toxicity to humans, low toxicity
to the bacteria, immiscibility with water, an appropriately high boiling point, and should
form no emulsion with the bioreactor constituents. The distribution of solute between
solvent and aqueous phases will determine the thermodynamic feasibility and the amount
of solvent required to remove the end product. Typical solvents include secondary and
tertiary amines in a suitable solvent, tributyl phosphate, ethyl acetate, tri-octyl phosphine
oxide and related compounds in a suitable co -solvent, long chain alcohols, hexane,
cyclohexane, chloroform, and tetrachloroethylene.
The nutrients and materials in the aqueous phase (30) pass back to the bioreactor (12) and
the solvent/acid/water solution (32) passes to a distillation column (34), where it is
heated to a sufficient temperature to separate the solvent (28) from the acid and water
(36). The solvent (28) passes from the distillation column (34) through a cooling
chamber (3 8) to lower the temperature to the optimum temperature for extraction, then
back to the extraction chamber (26) for reuse. The acid and water solution (36) passes to
a final distillation column (40) where the desired end product (42) is separated from the
water and removed. The water (44) is recirculated for nutrient preparation.
FIG. 2 shows a process for the production of the road deicer, calcium magnesium acetate
(CMA) (46), from waste gas (48). The process is identical to the acetic acid process of
FIG. 1 through solvent extraction. Identical organisms, nutrients and process conditions
are used in continuous fermentation, including the reaction vessels. Similarly, cell
recycle by hollow fiber membrane, centrifugation or other filtration devices are
identically employed in this process. Finally, the extraction of acetic acid in an extraction
chamber, followed by recycle of the acid -free medium, is employed.
After extraction, the process for producing CMA differs greatly from the acetic acid
production process of FIG. 1. In the CMA process the solvent (50) containing acetic acid
and a small amount of water is sent to a reaction vessel (52) for CMA production. The
water content of the solvent stream is dependent upon the solvent used for acetic acid
extraction. Again, solvents such as secondary and tertiary amines in a suitable co -solvent,
tributyl phosphate, ethyl acetate, tri-octyl phosphine oxide and related compounds in a
suitable co -solvent, long chain alcohols, hexane, cyclohexane, chloroform and
tetrachloroethylene may be employed with varying success. The reaction vessel (52) for
CMA is most suitably a Continuous Stirred Tank Reactor (CSTR), although other reactor
systems may be employed. A mixture (54) of dolomitic lime and magnesium oxide in
water is added to the solvent containing acetic acid and water. Reaction occurs to
produce CMA in aqueous solution at or below the saturation level.
The CMA, water and solvent (56) are then sent to a settling device (58) to separate the
aqueous and solvent phases. The solvent phase (60) is returned to the extraction chamber
for recycle. The CMA/water (62) is sent to drying/pelletizing means (64) to produce a
pelletized CMA product.
Potassium acetate (KA) can be produced as an alternative product by substituting caustic
potash (or potassium oxide) for the dolomitic lime. Since KA is produced as a 50 percent
aqueous solution, drying and pelletizing are not required.
FIG. 3 shows a process of this invention for the production of ethanol from waste gas. As
in FIG. 1, water gas (66) and nutrients (68) are fed into a reactor (70) containing a culture
of microorganisms. The reactor may be any of the types described above in the narrative
of FIG. 1. The organism used in the ethanol production process must be capable of
producing ethanol in place of acetic acid/acetate. In general, a low fermentation pH of
4.0-5.5 is required, coupled with a nutrient limitation. The bacteria listed hereinabove
which are capable of operating at these reduced pH levels can be used in this process of
ethanol production.
Waste gas is fed into the reactor containing the culture of organisms capable of ethanol
production along with the required nutrients. Ethanol is produced as the product in a
similar fashion as in FIG. 1. Cell recycle (72) may be used to enhance the cell
concentration in the reactor, but this operation is not required to make the process work.
The permeate (74) from the cell recycle apparatus containing dilute ethanol in medium is
sent to distillation (76), where the water (78) and ethanol (80) are separated. Ninety-five
percent ethanol exits the top of the distillation column and water (spent medium) exits
the bottom of the column. The spent medium is sent back to the reactor as water recycle.
The 95 percent ethanol is sent to a molecular sieve system (82) to produce anhydrous
ethanol (84).
Thus in accordance with the present invention, it is now possible to produce valuable
organic acids, alcohols, or organic acid salts by a gaseous substrate fermentation, not
only reducing consumption of valuable chemical feedstocks, but also removing
hazardous atmospheric pollutants from the waste gas streams of many industries.
Previous processes to derive these chemicals biologically were based on fermentation of
sugars.
In the processes described hereinabove, it is preferred that the process is conducted at
higher than 1 atmosphere. Preferably, it is preferred that it be conducted at pressures up
to 320 atmospheres, and more preferably up to 20 atmospheres, and most preferably up to
15 atmospheres.
The following specific examples are submitted to illustrate but not to limit the present
invention. Unless otherwise indicated, all parts and percentages in the specification and
claims are based upon volume.
EXAMPLE I
Production of Acetic Acid from Carbon Black Waste Gases
This example is directed to a process utilized to convert waste gas of a composition
which matches that of the furnace exhaust of carbon black manufacture to acetic acid.
The waste gas has a composition of about 13 percent carbon monoxide, 14 percent
hydrogen, and 5 percent carbon dioxide, with the remaining 68 percent largely nitrogen,
with traces of oxygen and sulfur compounds. The waste gases are produced as the result
of partial oxidation of gas or oil with insufficient air to form amorphous carbon, with
about 1.2 pounds of carbon monoxide produced per pound of elemental carbon. These
waste gases form a serious atmospheric contamination problem and also represent a
valuable chemical feedstock resource not presently being recovered.
In the development of the present process, two distinct routes to produce acetic acid from
carbon black waste gases were studied. The direct route converts carbon monoxide and
water, or hydrogen and carbon dioxide, directly into acetic acid according to Equations
(1) and (2), respectively. An indirect route involves the conversion of carbon monoxide
and water into hydrogen and carbon dioxide by the water gas shift reaction, followed by
production of acetic acid from hydrogen and carbon dioxide. This indirect route was
found to be a less efficient utilization of the technology. The acetogens tested are
summarized in Table 1.
TABLE 1
Acetogenic Bacteria Tested for CO, H.sub.2, and CO.sub.2 Conversion
Simultaneous
Bacterial Route Consumption of CO and H.sub.2
Direct Route
P.
productus
No
E.limosum
No
A.
noterae
No
C.
aceticum
No
C.
thermoaceticum
No
S.
sphaeroides
No
A.
woodii
Yes
A.
kivui
Yes
C.
ljungdahlii ERI2
Yes
Indirect Route
R.
gelatinosa
No
R.
rubrum
No
Among these bacteria that produce acetic acid directly from carbon monoxide, A. kivui
and the newly isolated strain, C. 1jungdahlii ERI2, show far superior rates for both carbon
monoxide and hydrogen utilization. Further experimentation proceeded using these two
anaerobic bacteria. There are obvious advantages to the use of bacteria that can utilize
carbon monoxide and hydrogen simultaneously. Such use would afford the most efficient
use of the waste gases and remove the greatest amount of atmospheric pollutants.
A. Bench Scale Operation of the Described Process to Produce Acetic Acid
As shown in FIG. 4 and in accordance with one embodiment of the present invention, a
bench scale continuous conversion system is shown to include a BioFlo IIC fermentor
(150) [New Brunswick Scientific Co., Inc., Edison, N.J.]. The fermentor (150) is
equipped with an agitation motor, pH controller, foam controller, thermostat, dissolved
oxygen probe, nutrient pump, and 2.5 L culture vessel. The working volume is variable
(1.5-2.0 L). Other variable operational parameters include medium feeding rate (Dilution
rate), gas flow rate (Gas retention time), and agitation (rpm). The vented or exhaust gases
exit the fermentor (150) through a condenser fixed to a vented hood via a water trap and
a sampling port.
The culture broth (152) is recycled through a cross-flow hollow fiber module (154) by a
peristaltic pump [Cole Parmer]. The recycling rate is about 80-100 mL/minute. The
hollow fiber module (154) has the following characteristics: the surface area is 0.35
ft.sup.2, the pore size is 0.2 .mu.m and the lumen diameter is 1 mm. The permeate (156)
is pumped to a storage tank (158) (Feed storage). The culture cells are returned to the
fermenter along line (155).
A countercurrent acetic acid extraction system, including two stage mixer and settler
components includes first and second mixers (160) and (162) and first and second
settling tanks (164) and (166). The permeate (168) from storage (158) is pumped to
mixer (160) through a flow controller (170). The solvent (172) is pumped to mixer (162)
from solvent storage (174) through a flow controller (176). Both mixer (160) and mixer
(162) are equipped with stirring mechanisms to achieve good mixing of aqueous phase
and solvent phase. The mixture of both phases from the mixers (160) and (162) is led to
settlers (164) and (166), respectively. The phase separation is accomplished in the
settlers. The aqueous phase (178) from settler (164) is pumped to mixer (162); the
solvent phase (180) from settler (164) is pumped to a separator (182); the aqueous phase
(184) from settler (166) is pumped to raffinate storage (186); and the solvent phase (188)
from settler (166) is pumped to mixer (160). The raffinate is recycled to the CSTR 50
along a line (190). This recycle line (190) is partially bled at (192) to remove inhibiting
factors.
The solvent (180) loaded with acetic acid is pumped to a distillation flask (194) through a
preheater (196). The distillation flask (194) is equipped with two thermocouples (196)
and (198) to monitor and control temperature in the liquid phase and gas phase. The
heating temperature for distillation is set to achieve maximum vaporization of the acetic
acid. The acetic acid vapors are condensed in a condenser (100) and collected in a flask
(102). The stripped solvent (104) is pumped through a cooling soil (106) to solvent
storage (174).
A bench scale operation of the described process as diagramed in FIG. 4 was fabricated
in the laboratory to determine quantitative yields under optimized conditions. The
nutrient mixture fed to the culture was as follows:
1. 80.0 ml of a salt, composed o£
KH.sub.2 PO.sub.4
K.sub.2 HPO.sub.4
(NH.sub.4).sub.2 SO.sub.4,
NaCl 6.00 g/L
MgSO.sub.4.2H.sub.2 O
2. 1.0 g of yeast extract
3. 1.0 g of trypticase
3.00 g/L
3.00 g/L
6.00 g/L
1.25 g/L
4. 3.0 ml of PFN trace metal solution (Pfenning) containing:
FeCl.sub.2 * 4H.sub.2 O 1500 mg
ZnSO.sub.4 * 7H.sub.2 O 100 mg
MnCl.sub.2 * 4H.sub.2 0 30 mg
H.sub.3 BO.sub.3
300 mg
CoCl.sub.2 * 6H.sub.2 O
200 mg
CuCl.sub.2 * H.sub.2 O
10 mg
NiCl.sub.2 * 6H.sub.2 O
20 mg
NaMoO.sub.4 * 2H.sub.2 O 30 mg
Na.sub.2 SeO.sub.3
10 mg
Distilled water 1000 ml
10.0 ml of B vitamins:
Pyridoxal HCl
10 mg
Riboflavin
50 mg
Thiamine HCl
50 mg
Nicotinic acid
50 mg
Ca-D-Pantotheinate
50 mg
Lipoic Acid
60 mg
P-aminobenzoic acid
50 mg
Folic acid
20 mg
Biotin
20 mg
Cyanocobalamin
50 mg
Distilled water
1000 ml
6. 0.5 g of Cysteine HCl
7. 0.6 g of CaCl.sub.2.2H.sub.2 O
8. 2.0 g of NaHCO.sub.3
9. 1.0 ml of Resazurin (0.01 %)
10. 920.0 ml of distilled water
For use with A. kivui, the nutrient solution was pH adjusted to 6.6, whereas for the new
strain, C. ljungdahlii ERI2, the pH was adjusted to 4.9. The ability to operate at a lower
pH is a great advantage in acetic acid recovery. The solution was then sparged for 20
minutes with a 20% CO.sub.2 and 80% N.sub.2 atmosphere, then transferred
anaerobically and autoclaved for 15 minutes.
B. CSTR Experiments Utilizing the Bacterial Strains A. kiwi and C. ]jungdahlii ERI2
Numerous experiments were carried out with Continuous Stirred Reactors (CSTR). The
results obtained are exemplified in the following data. The bench scale system operating
with the CSTR and the anaerobic bacteria, C. ]jungdahlii ERI2 and A. kiwi, consisted of
a New Brunswick Scientific Bioflo IIe fermenter, a hollow fiber membrane unit for cell
recycle, and extraction and distillation columns. Nutrient mixture was fed into the
bioreactor at a rate of 3.2 cubic centimeters per minute. Capacity of the reactor was 2.5
liters, within which a constant fluid level of 1.5 liters was maintained. The fluid was
agitated at variable rates of up to 1000 revolutions per minute with gas introduced at a
rate of approximately 500 cubic centimeters per minute. Optimal gas retention times
were in the range of three minutes. The gas feed varied with its uptake by the bacteria,
which was in tum a function of the cell density. The liquid from the bioreactor was
passed to the hollow fiber membrane at a rate of 55 to 70 milliliters per minute. From the
hollow fiber membrane, permeate was gathered at a rate of 1.5 milliliters per minute.
Analysis of this permeate indicates the acetic acid/acetate concentration at this stage to
range in excess of 20 grams per liter. Operating at a pH of 4.9, 42 percent of this product
was in the acid form using C. ljungdahlii ER12. For A. kiwi, the acid yield was only 1.4
percent. Results of various runs for the two bacteria, including conversion rates and
product yields are summarized in Tables 2A, 213, 3A and 3B as follows:
TABLE2B
Summary of ER12 Experiments in the CSTR with Cell Recycle
Dry Cell Product
Weight Concentration Specific
Exp. Concentration HAC ETOH Productivities
No. (g/L) (g/L) (P/I-) (g/L h) (g/g hr)
1 2.3 9.7 0.07 0.43 0.18
TABLE 2A
Summary of ERI2 Experiments in the CSTR
with Cell Recycle
Gas
Retention
Liquid
Agitation Percent Gas
Exp
Time
Dilution Rate Conversion
No.
(min)
Rate(hr.sup.-1)
(rpm)
CO H.sub.2
1
9.30
0.056
750
80.75
74.5
2
9.28
0.055
750
82.1
72.0
3
6.14
0.061
750
73.6
46.5
4
6.4
0.08
750
74.8
49.6
5
4.74
0.087
750
68.5
37.2
6
4.91
0.10
750
68.8
50.2
7
4.05
0.102
750
65.5
58.1
8
3.98
0.103
900
74.3
67.9
9
2.89
0.117
900
66.1
33.9
10
3.28
0.105
1000
74.6
51.3
11
3.22
0.125
1000
73.1
54.0
12
2.63
0.13
1000
68.9
44.0
13
2.3
0.134
1000
66.0
38.7
14
2.7
0.11
1000
72.7
67.7
15
2.4
0.11
1000
68.6
63.3
16
2.53
0.122
1000
72.1
67.4
17
3.0
0.13
1000
76.6
73.3
TABLE2B
Summary of ER12 Experiments in the CSTR with Cell Recycle
Dry Cell Product
Weight Concentration Specific
Exp. Concentration HAC ETOH Productivities
No. (g/L) (g/L) (P/I-) (g/L h) (g/g hr)
1 2.3 9.7 0.07 0.43 0.18
2
3.32
9.56
0.094 0.52 0.16
3
4.11
12.78
0.125 0.78 0.19
4
5.02
12.98
0.125 1.05 0.19
5
4.79
12.38
0.125 1.08 0.23
6
4.53
10.73
0.05 1.08 0.24
7
5.27
11.49
0.076 1.17 0.22
8
6.17
12.73
0.1 1.31 0.21
9
5.91
11.69
0.04 1.38 0.23
10
7.30
12.83
0.13 1.35 0.18
11
10.25
13.57
0.08 1.71 0.17
12
11.0
14.63
0.12 1.90 0.17
13
11.1
20.59
0.113 2.77 0.25
14
8.37
25.62
0.27 2.88 0.34
15
9.83
25.62
0.36 2.95 0.30
16
9.82
25.62
0.72 3.12 0.32
17
12.4
22.33
0.52 2.90 0.23
TABLE 3A
Summary of A. kivui Experiments in the CSTR with Cell Recycle
Gas
Retention
Liquid
Agitation Percent Gas
Exp
Time
Dilution Rate Conversion
No.
(min)
Rate (hr.sup.-1) (rpm) CO H.sub.2
1
5.0
0.058
750 67.8 44.2
2
4.4
0.958
750 65.7 38.5
3
4.3
0.058
900 71.3 40.7
4
3.72
0.058
900 69.0 37.3
5
3.72
0.076
900 70.3 41.1
6
3.2
0.076
900 66.4 41.4
7
2.8
0.076
900 61.5 29.1
8
2.8
0.076
1000 69.5 36.3
9
2.8
0.11
1000 70.2 41.6
10
2.2
0.11
1000 64.0 25.0
TABLE
3B
Summary of A. kivui
Experiments in the CSTR with Cell Recycle
Dry Cell
Weight
Product Specific
Exp.
Concentration Concentration Productivities
No.
(P/L)
(g/L) (P/L hr) (gig hr)
1
4.00
16.15
0.96 0.24
2
4.8
16.63
0.94 0.19
3
4.5
17.03
0.99 0.21
4
5.14
19.16
1.13 0.22
5
5.28
16.17
1.21
0.23
6
5.71
16.85
1.23
0.23
7
5.00
16.16
1.22
0.23
8
5.8
18.58
1.62
0.29
9
5.9
18.4
1.84
0.36
10
7.2
16.5
2.1
0.3
C. ICR Experiments Utilizing the Bacterial Strain C. Ijungdahlii ERI2
Numerous experiments were carried out with Immobilized Cell Reactors (ICR). The
results obtained are exemplified in the following data. An ICR, consisting of a 2 inch
outside diameter by 24 inch tall glass tube packed with fabric to support the cells and
Enkamat 7020 immobilizing medium, was also tested in the acetic acid production
process. With C. Ijungdahlii ER12 as the acetogenic anaerobe, 100 percent of the carbon
monoxide and 79 percent of the hydrogen were converted at a gas retention time of 20
minutes. Acetic acid concentrations in the removed liquid were approximately 6.0 grams
per liter. Results of the ICR studies are summarized in Table 4.
TABLE 4
Fabric ICR Performance with ERI2
Liquid Gas Re- Product
Dilution tention H.sub.2 CO Cell Concentration
Rate Time Conversion Conversion Concen. HAC ETOH
(hr) (min) (%) (%) (g/L) (g/L) (g/L)
0.23 4.83 38.62 54.66 .125 3.221 .778
7.41 49.15 70.87 .120 2.690 .620
11.66 51.31 80.61 .067
13.61 56.87 83.93 .064 2.099 .201
0.17 6.39 48.15 73.27 .161 3.382 1.365
11.21 68.96 92.82 .143 3.189 .495
55.44 83.13 96.27 .112 .813 .058
0.12 6.26 43.89 70.76 .094 3.864 1.689
0.09 7.87 42.40 79.72 .095 4.423 2.733
19.82 59.63 92.92 .102
0.03 22.14 55.01 94.21 .071 4.878 2.631
29.00 78.60 100 .018 5.604 2.743
60.48 83.33 100
The ICR has a certain attractiveness on an industrial scale in that the energy costs to
operate the reactor are reduced significantly. The proper selection of packing materials,
solution phases, and pressures may yield production approaching that of the CSTR.
D. Acetic Acid Recovery
Various solvents were tested for recovering acetic acid from the permeate, and the results
are summarized in Table 5. Tributyl phosphate was identified as having both a high
distribution coefficient and a high boiling point. The solvent and permeate from the cell
separator were commingled in a two stage extraction process. Alternatively, an extraction
column could be used. Permeate was introduced into a 3 liter flask where it was mixed
with incoming solvent. A ratio of 1 part solvent to 1 part permeate worked well and gave
high recovery rates. The combined fluids were passed from the mixer to a 4 liter settling
chamber where the solvent/acetic acid mixture separate as a lower density phase from the
water and nutrients. Retention times of approximately 15 minutes were used in the
settling tanks. The lower density phase was extracted and fed to a distillation flask.
The raffinate was passed from the first settler to a second mixer where it was contacted
again with solvent, then removed to a second settling chamber. This allowed for more
complete extraction of the acetic acid; acid recovery increased from 82 percent to greater
than 96 percent using tributyl phosphate. The solvent/acetic acid mixture from this settler
was returned to the first mixer, while the raffinate of water and organics was passed back
to the bioreactor.
The distillation unit was a 5 liter flask with a boiling mantle. A common distillation
column, with reflux, could be used for complete acid recovery. Because of the high
boiling point of tributyl phosphate, nearly complete recovery is accomplished in one step.
The solvent/acetic acid mixture was heated to 120.degree. C., with the acetic acid
collected overhead in a condensing coil. In this single stage system, distillation
efficiencies of 70 percent were achieved.
TABLE 5
Acetic Acid Distribution Coefficient Study
Equilibrium
Aqueous Acetic
Acetic Acid
Acid Concentration
Distribution
Solvent
(g/L) Coefficients
Hexane
6.559
0.0
Decane
5.968
0.08
Chloroform
5.128
0.09
Kerosene
4.648
0.11
Hexadecane
5.866
1.13
Dodecane
4.654
0.13
Dodecyl acetate
5.787
0.15
Dibutyl phosphate
4.615
0.18
Oleyl alcohol
5.114
0.28
Trioctylamine
3.785
0.31
Undecyl alcohol
4.528
0.40
Ethyl acetate
4.550
0.41
Ethyl butyrate
4.665
0.42
Dexyl alcohol
3.890
0.42
Octan]
4.358
0.45
Nonyl alcohol
3.470
0.55
2-ethyl-l-hexanol
3.308
0.77
3-methylcyclohexanol
2.110
1.26
Cyclohexanone
2.702
1.66
Tributyl Phosphate
1.657
2.38
Solvent mixtures were also tried and distribution coefficients of mixed solvents are
summarized in Table 6.
TABLE 6
Distribution Coefficients of Mixed Solvents
Distribution Percent
Solvent Mix Coefficients Increase
Oleyl Alcohol (10 cc) 0.17
Oleyl Alcohol (10 cc) + Cyc (1 cc)
0.31 72
Oleyl Alcohol (10 cc) + TBP (1 cc)
0.29 61
Oleyl Alcohol (10 cc) + Cyc (2 cc)
0.45 150
Oleyl Alcohol (10 cc) + TBP (2 cc)
0.42 133
Oleyl Alcohol (10 cc) + Cyc (3 cc)
0.36 100
Oleyl Alcohol (10 cc) + TBP (3 cc)
0.42 133
Oleyl Alcohol (10 cc) + Cyc (4 cc)
0.35 94
Oleyl Alcohol (10 cc) + TBP (4 cc)
0.40 122
Oleyl Alcohol (10 cc) + Cyc (6 cc)
0.52 188
Oleyl Alcohol (10 cc) + TBP (6 cc)
0.65 261
Oleyl Alcohol (10 cc) + Cyc (7 cc)
0.69 283
Oleyl Alcohol (10 cc) + TBP (7 cc)
0.74 311
EXAMPLE 2
Production of Acetic Acid from Carbon Black Waste Gases at Higher Pressures
Mass transport in the cellular reactions can be further enhanced by operating the system
at increased pressures. Simple batch experiments were carried out to test the dynamics of
this system. It was found that reaction rates increased in linear proportion to the pressure,
with a corresponding reduction in effective retention time.
Another advantage to operating at increased pressure is that reactor volume can also be
reduced in linear fashion, i.e. operation at 10 atmospheres pressure requires a reactor
with one tenth the volume of a reactor operating at 1 atmosphere. FIGS. 5 and 6 show the
increase in cell density and acetic acid concentration, respectively, with the increased
pressure. This acetic acid concentration far exceeds typical batch concentrations for a
batch reactor at atmospheric pressure.
EXAMPLE 3
Production of Acetic Acid from Carbon Black Waste Gases with Surfactants
Mass transport is also increased by the use of surfactants. Table 7 presents the results of
carbon monoxide uptake tests performed on C. ljungdahlii ER12 in the presence of
various commercial surfactants. In each case, the control value of 100 (percent)
represents carbon dioxide uptake in batch fermentation, and the sample value, the
percentage of the control in batch fermentation in the presence of the surfactant.
TABLE 7
CO Consumption by ERI2 in the Presence of Surfactants
Control*
With Surfactant
DNAP (0.1%, v/v)
100
0
Nondiet P-40 (0.1%, v/v)
100
0
Tergitol NP -10 (0.1 %, v/v)
100
0
Tergitol Min Foam IX (0.1%,
v/v) 100 0
Tergitol TMN-10 (0.1%, v/v)
100
0
Triton X-15 (0.1 %, v/v)
100
0
Triton X-100 (0.1 %, v/v)
100
0
Triton X-114 (0.1%, v/v)
100
0
Triton N-101 (0.1%, v/v)
100
5.83
Triton X-405 (0.1 %, v/v)
100
7.82
Tergitol 8 (0.1%, v/v)
100
12.15
Triton N-42 (0.1%, v/v)
100
42.90
Witconol NS -500K (0.1 %, v/v) 100
79.08
Tween 85 (0.1 %, v/v)
100
82.16
Witconol H-33 (0.1%, v/v)
100
90.12
Witconol 6903 (0.1%, v/v)
100
92.39
Tween 80 (0.1 %, v/v)
100
97.15
Arlacel 83 (0.1%, v/v)
100
97.43
Span 80 (0.1%, v/v)
100
99.12
Tyloxapol (0.l %, v/v)
100
104.86
Witconol 5906 (0.1%, v/v)
100
108.42
Span 85 (0.1%, v/v)
100
124.85
W-1 (0.001%, w/v) First time
100
105.89
Second time regas
100
0
Brij 96 (0.004%, w/v) First time 100
107.98
Second time regas
100
0
EXAMPLE 4
Production of CMA from Carbon Black Waste Gas
Carbon black waste gas containing about 14 percent CO, 17 percent H.sub.2, and 4
percent CO.sub.2, as the major components in N.sub.2 is spared into a 160 L CSTR,
maintained at 6 atm 37.degree. C., and containing Clostridium ljungdahlii ER12 ATCC
deposit 55380. The waste gases are produced as the result of partial oxidation of
hydrocarbons with insufficient air to form amorphous carbon, with about 1.2 pounds of
carbon monoxide produced per pound of elemental carbon. These waste gases form a
serious atmospheric contamination problem and also represent a valuable chemical
feedstock resource not presently being recovered. The gas retention time (defined as the
ratio of the reactor volume to the gas flow rate at standard conditions) is maintained at
0.52 minute.
An aqueous liquid medium containing water, base salts, B -vitamins, a nitrogen source
and a sulfide source is fed to the reactor at a liquid dilution rate (defined as the ratio of
the liquid flow rate to the reactor volume) of 1.05 hour.sup.-1. The agitation rate in this
reactor is 322 rpm, the temperature is 37.degree. C. and the operating pH is 5.03. Under
these conditions, the conversion of CO was 83 percent and the conversion of H.sub.2 was
54 percent. A hollow fiber membrane cell recycle unit is used to maintain a cell
concentration of 10.5 g/L inside the reactor.
The dilute acetic acid/acetate product stream from the reactor containing 13.2 g/L acetic
acid/acetate is sent to a three stage countercurrent extraction device, where it is extracted
with solvent. The solvent to feed ratio is 1 to 4. The acetic acid in the acetic acid/acetate
product stream is 3.7 g/L. The acetic acid concentration in the solvent leaving the
extractor is 16.7 g/L. Water (medium) from extraction is sent back to the fermenter as
recycle.
Dolomitic lime/MgO is added to the acetic acid directly in the solvent phase to form
CMA. After reaction the saturated CMA solution is sent to drying and pelletizing. CMA
(1.15 lb) containing a Ca.sup.2+ /Mg.sup.2+ in a molar ratio of 3/7 is formed per pound
of acetic acid.
EXAMPLE 5
Production of Acetic Acid from Carbon Black Waste Gas
Carbon black waste gas containing about 14 percent CO, 17 percent H.sub.2, and 4
percent CO.sub.2 in N.sub.2 is spared into a 144 L trickle bed reactor operating at 1.58
atm, 37.degree. C. and containing Clostridium ljungdahlii ER12 ATCC deposit 55380. A
trickle bed reactor is a column packed with a commercial packing such as Raschig rings
or Berl saddles in which liquid and gas are contacted with each other due to flow through
the column. In the present example, the liquid and gas both enter the column from the top
in a concurrent fashion, although countercurrent flow (gas entering the bottom, liquid
entering the top) is possible. The gas retention time is maintained at 0.46 minute and the
liquid medium dilution rate is 0.57 hour.sup.-l. The liquid medium contains the same
constituents as in Example 1. Agitation in the reactor is provided by liquid recirculation,
using a recirculation rate of 60 gpm. The operating pH in the reactor is 5.05. Under these
conditions, the CO conversion is 57 percent and the H.sub.2 conversion is 58 percent. A
hollow fiber unit is used to maintain a cell concentration of 13.6 g/L inside the reactor.
The dilute acetic acid/acetate product stream containing 6.4 g/L combined acetic
acid/acetate and 2 g/L acetic acid is sent to a three stage countercurrent extraction
column. The solvent to feed ratio is 1:4. The acetic acid in the solvent leaving the
extractor is 10 g/L. Water (medium) from the extraction unit is sent back as recycle to the
reactor.
The solvent containing the acetic acid is sent to distillation to recover the acid and
solvent. A vacuum solvent distillation column and an acetic acid distillation column are
used in the separation. Glacial acetic acid is produced as the final product.
EXAMPLE 6
Production of Potassium Acetate from Carbon Black Waste Gas
The carbon black waste gas of Example 4 is used to make potassium acetate instead of
CMA. All fermentation and solvent extraction conditions remain the same. Caustic
potash (potassium oxide) is used to react with the acetic acid to form a 50 percent
solution of potassium acetate directly in the solvent phase.
EXAMPLE 7
Production SCP from Coke Oven Waste Gas
A coke oven waste gas containing about 6 percent CO, 2 percent CO.sub.2, 57 percent
H.sub.2, 5 percent N.sub.2, and 27 percent gaseous hydrocarbon is fed to a CSTR with
cell recycle as described previously in Example 4. The reactor is used to produce a
product such as dilute acetic acid or ethanol. In addition, the cell concentration inside the
reactor is 13.6 g/L. These cells (microorganisms) can be harvested to produce bacterial
single cell protein as an animal feed. A purge stream from the reactor containing cells is
sent to a dryer to process dry single cell protein.
I7RI_NVA120T.i
Production of H.sub.2 from Refinery Waste Gas
Refinery waste gas containing about 45 percent CO, 50 percent H.sub.2 and 5 percent
CH.sub.4 is spared into a 1 L CSTR operating at 50.degree. C. and a few inches of water
pressure containing Bacillus smithii ERIH2 which was deposited on Mar. 18, 1993 with
the American Type Culture Collection, and given deposit accession no. 55404. This
deposit was released to the public on Oct. 13, 1998. The medium to the reactor is 1.0 g/L
com steep liquor. Carbon monoxide in the waste gas is converted along with water to
CO.sub.2 and H.sub.2. With a 90 percent conversion, the exit gas stream contains 3.2
percent CO, 64.4 percent H.sub.2, 28.8 percent CO.sub.2 and 3.6 percent CH.sub.4. The
CO, CO.sub.2 and CH.sub.4 are removed from the gas stream by solvent extraction.
EXAMPLE 9
Production of Other Chemicals from Carbon Black Waste Gas
Carbon black waste gas containing about 14 percent CO, 17 percent H.sub.2 and 4
percent CH.sub.4 in N.sub.2 is spared into a 1 L CSTR operating at 37.degree. C. and a
few inches of water pressure. The medium in the reactor is a basal salts mixture
containing water, 13 -vitamins, salts and minerals. The single or mixed culture in the
reactor produces a liquid phase product of methanol, propanol, buytanol, propionic acid,
butyric acid or other desirable products. The system is set up essentially the same as in
Example 8.
Following dilute product formation, the product is recovered in a suitable product
recovery system consisting of extraction, distillation or other well-known product
recovery techniques. If multiple products are produced, a stagewise product recovery
system is employed.
EXAMPLE 10
Production of Products from Waste Gas Using a Mixed Culture
The oil refinery waste gases of Example 8 are spared into a 1.0 L CSTR without cell
recycle containing a mixed culture of bacteria capable of producing ethanol as the final
product. The mixed culture contains one or more anaerobic bacteria that are capable of
producing ethanol at low pH and under nutrient limitation. Other strains can also be
present. The conditions inside the reactor are essentially identical to the conditions of
Example 8. The product from the reactor is 15-20 g/L ethanol and 3-6 g/L acetic acid.
The product stream from the reactor is treated identically to the method described in
Example 8.
EXAMPLE 11
Production of Ethanol from Waste Gas Using C. Ijungdahlii PETC
The oil refinery waste gases of Example 8 are spared into a 1.0 L CSTR without cell
recycle containing a culture of C. 1jungdahlii PETC capable of producing ethanol as the
final product. The conditions inside the reactor are essentially identical to the conditions
of Example 8. The product from the reactor is 15 g/L ethanol and 6 g/L acetic acid. The
product stream from the reactor is treated identically to the method described in Example
8.
Thus, it will be appreciated that as a result of the present invention, a highly effective
improved process for converting waste gases to acids, including organic acids, e.g., acetic
acid, alcohols, hydrogen, SCP or organic acid salts is provided by which the principle
objective, among others, is completely fulfilled. It is contemplated and will be apparent
to those skilled in the art from the preceding description and accompanying drawings that
modifications and/or changes may be made in the illustrated embodiments without
departure from the present invention. Accordingly, it is expressly intended that the
foregoing description and accompanying drawings are illustrative of preferred
embodiments only, and are not limiting, and that the true spirit and scope of the present
invention be determined by reference to the appended claims.
K
United States Patent 5,821,111
Gaddy, et al. October 13, 1998
Bioconversion of waste biomass to useful products
Abstract
A process is provided for converting waste biomass to useful products by gasifying the
biomass to produce synthesis gas and converting the synthesis gas substrate to one or
more useful products. The present invention is directed to the conversion of biomass
wastes including municipal solid waste, sewage sludge, plastic, tires, agricultural
residues and the like, as well as coal, to useful products such as hydrogen, ethanol and
acetic acid. The overall process includes the steps of gasifying the waste biomass to
produce raw synthesis gas, cooling the synthesis gas, converting the synthesis gas to the
desired product or products using anaerobic bioconversion, and then recovering the
product or products. In accordance with a particular embodiment of the present
invention, waste biomass is converted to synthesis gas containing carbon monoxide and,
then, the carbon monoxide is converted to hydrogen by an anaerobic microorganism
ERIH2, bacillus smithii ATCC No. 55404.
Inventors: Gaddy; James L. (Fayetteville, AR); Chen; Guang Jiong (Fayetteville, AR)
Assignee: Bioengineering Resources, Inc. (Fayetteville, AR)
Appl. No.: 808088
Filed: February 28, 1997
Current U.S. Class: 435/252.5; 435/135; 435/139; 435/140; 435/168;
435/832
Intern') Class: C12P 001/04; C12P 003/00; C12N 001/20
Field of Search: 435/168,252.5,139,135,140,832
References Cited [Referenced By]
U.S. Patent Documents
4497637 Feb., 1985 Purdy et al. 48/111.
4515759 May., 1985 Burnes et al. 423/220.
4553981 Nov., 1985 Fuderer 48/62.
4568644 Feb., 1986 Wang et al. 435/161.
4652526 Mar., 1987 Hsu 435/253.
4692172 Sep., 1987 Stellaccio et al. 48/197.
4721676 Jan., 1988 Zeikus 435/253.
4732855 Mar., 1988 Zeikus et al. 435/141.
4771001 Sep., 1988 Bailey et al. 435/139.
4919813 Apr., 1990 Weaver 210/603.
4921799 May., 1990 Kitaura et al. 435/167.
4935360 Jun., 1990 Klemps et al. 435/140.
4994093 Feb., 1991 Wetzel et al. 48/197.
5026647 Jun., 1991 Tomes et al. 435/244.
5036005 Jul., 1991 Tedder 435/161.
5059288 Oct., 1991 Curry 203/43.
5077208 Dec., 1991 Sublette 435/168.
5110319 May., 1992 Turpin et al. 44/451.
5134944 Aug., 1992 Keller et al. 110/234.
5173429
Dec., 1992 Gaddy
435/163.
5238469
Aug., 1993 Briesacher et al.
95/115.
5593886
Jan., 1997 Gaddy
435/252.
Foreign Patent Documents
0282750
Sep., 1988 EP
435/266.
282750A
Oct., 1987 DE.
Other References
Photoproduction of Molecular Hydrogen by Rhodospirillum Rubrum, Howard
Gest and Martin D. Kamen, Science, Jun. 3, 1949, vol. 109, pp. 558-559.
Proton Translocation Coupled to the Oxidation of Carbon Monoxide to CO.sub.2
and H.sub.2 in Methanosarcina Barkeri Michael Bott and Rudolf K. Thauer, pp.
469-472, 1989.
Identification of a Carbon Monoxide -Metabolizing Bacterium as a Strain of
Rhodopseudomonas Geletinosa (Molisch) van Niel, M.P. Dashekvicz and R.L.
Uffen, International Journal of Systematic Bacteriology, Apr. 1979, pp. 145-148.
Carbon Monoxide Fixation Into the Carboxyl Group of Acetate During Growth
of Acetobacterium Woodii and H.sub.2 and CO.sub.2, Gabriele Diekert and
Maria Ritter, FEMS Microbiology Letters 17 (1983), pp. 299-302.
Photosynthetic Carbon Metabolism in the Green and Purple Bacteria, R. C.
Fuller, Chapter 36, pp. 691-705, 1978.
Sulfinol Process Has Several Key Advantages, B. Gene Goar, The Oil and Gas
Journal, Jun. 30, 1969, pp. 117-120.
Oxidation of Hydrogen and Reduction of Methanol to Methane is the Sole
Energy Source for a Methanogen Isolated from Human Feces, Terry L. Miller
and M.J. Wolin, Journal of Bacteriology, Feb. 1983, pp. 1051-1055.
Association of Hydrogen Metabolism with Unitrophic or Mixotrophic Growth of
Methanosarcina barkeri in Carbon Monoxide, Jill M. O'Brien et al., Journal of
Bacteriology, Apr. 1984, pp. 373-375.
Fuel Gas from Municipal Waste in an Integrated Circulating Fluid -Bed
Gasification/Gas-Cleaning Process, Erik Rensfelt et al., 1988.
Carbon Monoxide Fixation into the Carboxyl Group of Acetyl Coenzyme A
During Autotrophic Growth fo Methanobacterium, E. Stuperich et al., FEBS
Letters, Vol. 152, No. 1, pp. 21-23, Feb. 1983.
Mutants of Rhodospirillum rubrum Obtained After Long -Term Anaerobic, Dark
Growth, R.L. Uffen et al., Journal of Bacteriology, Dec. 1971, pp. 1348-1356.
Anaerobic Growth of a Rhodopseudomonas Species in the Dark With Carbon
Monoxide as Sole Carbon and Energy Substrate, Robert L. Uffen, Proc. Nati.
Acad. Sci. USA, vol. 73, No. 9, pp. 3298-3302, Sep. 1976.
Hydrogenase, Nitrogenase, and Hydrogen Metabolism in the Photosynthetic
Bacteria, Paulette M. Vignais et al., Advances in Microbial Physiology vol. 26,
pp. 155-234, 1985.
Demain et al., "Industrial Microbiology and Biotechnology", AIM 1986, pp. 332-
335.
Crueger & Crueger, 'Biotechnology: A Textbook of Industrial Microbiology", 2d
Ed., Sinauer Assoc., Inc., pp. 74-89.
Biotechnology Company Set for Fayetteville, Patricia May, Springsdale Morning
News, Oct. 29, 1992, p. IA.
Industrial Innovations for Tomorrow, New Process Uses Bacteria To Transform
Waste Gases Into Useful Chemicals, U.S. Dept, of Energy Publication Aug.
1992.
The Production of Acetic Acid From Carbon Dioxide and Hydrogen by an
Anaerobic Bacterium, Tsuyoshi Morinaga and Naoki Kawada, Journal of
Biotechnology, 14 (1990). 187-194.
Biological Conversion of Coal Synthesis Gas to Methane; S. Barik et al., Energy
Progress, Vol. 7, No. 3, Sep., 1987, pp. 157-160.
Chemical and Fuel Production by Anaerobic Bacteria J.G. Zeikus, Annual
Review Microbiology, 1980, pp. 423-464.
Energy From Biomass and Wastes, H. Alden, E. Bjorkman, B.Espenas, L.
Waldheim, IGT, Mar. 1991.
Gas -Solid Pyrolysis of Tire Wastes --Kinetics and Material Balances of Batch
Pyrolysis of Used Tires, J. M. Bouvier, F. Charbel and M. Gelus, Resources and
Conservation, 1987, vol. 15, pp. 205-214.
Fermentation as an Advantageous Route for the Production of an Acetate Salt for
Roadway De -Icing, C. W. Marynowski, J. L. Jones, D. Tuse, and R. L.
Boughton, American Chemical Society, 1985, vol. 24, pp. 457-465.
Photosynthetic Carbon Metabolism in the Green and Purple Bacteria, "The
Photosynthetic Bacteria", ed. by R. K. Clayton and W. R. Sistrom, Plemun Press,
New York, pp. 691-705 (1978).
Biomethanation of Biomass Pyrolysis Gases, C.A. Tracey and E. Ashare, Solar
Energy Research Institute, Jun. 1981, pp. 1-148.
Bioconversion of Synthesis Gas Into Liquid of Gaseous Fuels, K.T. Klasson,
M.D. Ackerson, E.C. Clausen and J.L. Gaddy, Enzyme Microbiology
Technology Aug. 1992, vol. 14, pp. 602-608.
Production of Acetic Acid by Actogenium Kivui, R. klemps, S.M. Schoberth, H.
Sahm, Applied Microbiology and Biotechnology, 1987, pp. 229-234.
Mechanism of Acetate Synthesis from CO.sub.2 by Clostridium Acidiurici, L.J.
Waber and H.G. Wood, Journal Bacteriology, Nov. 1979, vol. 140, pp. 468-478.
Hydrogenase. Nitrogenase, and Hydrogen Metabolism in the Photosynthetic
Bacteria, P.M. Vignais, A. Colbeau, J.C. Willison, Y. Jouanneau, Advances in
Microbial Physiology, vol. 26, 1985, pp. 163-177.
Photoproduction of Molecular Hydrogen by Rhodopirillum Rubrum, H. Gest and
M.D. Kamen, Science Jun. 3, 1949, vol. 109, pp. 558-559.
A Comparative Study of the Light and Dark Fermentations of Organic Acids By
Rhodospirillum Rubrum, E. f. Kohlmiller, Jr., and H. Gest, Department of
Microbiology, School of Medicine, Western Reserve University, Cleveland 6,
Ohio, Dec. 5, 1950, vol. 61, pp. 269-282.
Carbon Monoxide Fixation Into the Carboxyl Group of Acetate During Growth
of Acetobacterium Woodii on H.sub.2 and CO.sub.2, G. Diekert and M. Ritter,
Federation of European Microbiological Societies, Microbiology Letters, 17
(1983) pp. 299-302.
Isolation From Soil and Properties of the Extreme Thermophile Clostridium
Thermohydrosulfuricum, Jurgen Wiegel et al, Journal of Bacteriology, Sep.
1979, pp. 800-810.
Solvent Equilibria of Carboxylic Acids from Water, James M. Wardell and C.
Judson King, Journal of Chemical and Engineering Data, vol. 23, No. 2, 1978,
pp. 144-148.
Removing Carboxylic Acids From Aqueous Wastes, CEP, May 1977 R. W.
Helsel, Hydroscience Environmental Systems, Knoxville, TN.
Acetogenium Kiwi, A New Thermophilic Hydrogenoxidizing, Acetogenic
Bacterium, J.A. Leigh et al, Arch. Microbiol., 129:275-280.
Sporomusa, A New Genus of Gram -Negative Anaerobic Bacteria Including
Sporomusa Sphaeroides Spec. Nov. and Sporomusa Ovata Spec. Nov., Moller et
al, Arch Microbiology (1984) 139:388-396.
Acetobacterium, A New Genus of Hydrogen -Oxidizing, Carbon Dioxide -
Reducing, Anaerobic Bacteria, Balch et al, International Journal of Systematic
Bacteriology, Oct. 1977, pp. 355-361.
Peptostreptococcus Products Strain That Grows Rapidly with CO as the Energy
Source, William H. Lorowitz and Marvin P. Bryant, Applied and Environmental
Microbiology, May 1984, pp. 70-74.
Growth of Eubacterium Limosum with Carbon Monoxide as the Energy Source,
B.R. Sharak Genthner and M.P. Bryant, Applied and Environmental
Microbiology, Jan. 1982, pp. 70-74.
Carbon Monoxide Metabolism of the Methylotrophic Acidogen Butyribacterium
Methylotrophicum, Lee Lynd R. Kerby and J.G. Zeikus, Journal of Bacteriology,
Jan. 1982, pp. 255-263.
Revival of the Name Clostridium Aceticum, Gerhard Gottschalk and Manfred
Braun, International Journal of Systematic Bacteriology, Oct. 1981, p. 476.
Hydrogen Utilization by Clostridia in Sewage Sludge, Kyoko Ohwaki and R.E.
Hungate, Applied and Environmental Microbiology, Jun. 1977, pp. 1270-1274.
Single -Carbon Catabolism in Acetogens: Analysis of Carbon Flow in
Acetobacterium Woodii and Butyribacterium Methylotrophicum by
Fermentation and sup. 14 C Nuclear Magnetic Resonance Measurement, R.
Kerby et al, Journal of Bacteriology, Sep. 1983, pp. 1208-1218.
Production of Acetic Acid by Clostridium Thermoaceticum in Batch and
Continuous Fermentations, K. Sugaya et al, Biotechnology and Bioengineering,
vol. XXVIII, (1986), pp. 678-683.
Isolation of a Strain of Clostridium Thermoaceticum Capable of Growth and
Production at Ph 4.5, Robert D. Schwartz and Frederick A. Keller Jr., Aplied and
Environmental Microbiology, Jan. 1982, pp. 117-123.
Acetic Acid Production by Clostridium Thermoaceticum in Ph -Controlled Batch
Fermentations at Acidic pH, Robert D. Schwartz and Frederick A. Keller Jr.,
Applied and Environmental Microbiology, Jun. 1982, pp. 1385-1392.
Characterization of the H.sub.2 --and Co -Dependent Chemolithotrophic
Potentials of the Acetogens Clostridium Thermoaceticum and Acetogenium
Kivui, Steven L. Daniel et al, Journal of Bacteriology, Aug. 1990, pp. 4464-
4471.
Clostridium Thermosaccharolyticum Strain Deficient in Acetate Production,
David M. Rothstein, Journal of Bacteriology, Jan. 1986, pp. 319-320.
Nickel Transport by the Thermophilic Acetogen Acetogenium Kivui, Applied
and Environmental Microbiology, May 1989, pp. 1078-1081.
Differential Effects of Sodium on Hydrogen- and Glucose -Dependent Growth of
the Acetogenic Bacterium Acetogenium Kivui, Hsuichih Yang and Harold L.
Drake, Applied and Environmental Microbiology, Jan. 1990, pp. 81-86.
Influence of Environmental Factors in the Production of R(-)-1,2-Propanediol by
Clostridium Thermosaccharolyticum, F. Sanchez-Riera et al, Biotechnology
Letters, vol. 9, No. 7, pp. 449-454.
Analysis if Hydrogen Metabolism in Methanosarcina Barkeri: Regulation of
Hdrogenase and Role of Co -Dehydrogenase in H.sub.2 Production, L. Bhatnagar,
J.A. Krzycki, and J.G. Zeikus, Federation of European Microbiological Societies,
Microbiology Letters, 41 (1987) pp. 337-343.
Identification of a Carbon Monoxide -Metabolizing Bacterium as a Strain of
Rhodopseudomonas Gelantinosa (Molisch) Van Niel, M.P. Dashekvicz and R.L.
Uffen, International Journal of Systematic Bacteriology, Apr. 1979, vol. 29, pp.
145-148.
Mutants of Rhodospirillum Rubnun Obtained After Long -Term Anaerobic, Dark
Growth, R.L. Uffen, C. Sybesma and R.S. Wolfe, Journal of Bacteriology, Dec.
1971, vol. 108, No. 3, pp. 1348-1356.
The Active Species on CO.sub.2 'Utilized by Reduced Ferredoxin: CO.sub.2
Oxidoreductase from Clostridium Pasteurianum, R.K. Thauer et al, European
Journal of Biochemistry, 55, 111-117 (1975).
Biological Production of Alcohols from Coal Through Indirect Liquefaction, S.
Bank et al, The Humana Press, 1988, pp. 363-378.
Biological Production of Liquid and Gaseous Fuels from Synthesis Gas, K.T.
Klasson et al, Applied Biochemistry and Biotechnology, vol. 24/25, 1990.
The Biological Production of Ethanol from Synthesis Gas, J.L. Vega et al,
Applied Biochemistry and Biotechnology, vol. 20/21, 1989.
Sulfinol Process Has Several Key Advantages, B.G. Goar, The Oil and Gas
Journal, Jun. 30, 1969, pp. 117-120.
Carbon Monoxide Fixation Into the Carboxyl Group of Acetyl Coenzyme a
During Autotrophic Growth of Methanobacterium, E. Stupperich, K.E. Hammel,
G. Fuchs and R.K. Thauer, Federation of European Biochemical Societes,
Microbiology Letters, vol. 152, No. 1, Feb. 1983, pp. 21-23.
Proton Translocation Coupled to the Oxidation of Carbon Monoxide To
CO.sub.2, and H.sub.2 In Methanosarcina Barkeri, M. Bott and R.K. Thauer,
European Journal of Biochemistry, 1989, pp. 469-472.
Photosynthesis in Rhodospirillum Rubrum I. Autotrophic Carbon Dioxide
Fixation, L. Anderson and R.C. Fuller, Plant Physiology, 1967, pp. 487-490.
Biological Upgrading of COA-Derived Synthesis Gas: Final Report (Abstract),
S. Barik, E.R. Johnson, C.W. Ko, E.C. Clausen, J.L. Gaddy, Fossil Fuels, vol.
110, 1989, p. 201.
Pyrolysis Process for Scrap Tires, S. Kawakami, K. Inoue, H. Tanaka, T. Sakai,
American Chemical Society Symposium Series, 130, 1980, Washington, DC.
Biomass and Wastes, Inst. Gas Tech., E. Rensfelt, C. Ekstrom, 1991.
Chemical and Fuel Production by Anaerobic Bacteria, J.G. Zeikus, Annual
Review of Microbiology, 1980, pp. 423-464.
Parameters Affecting the Kinetics of Ethanol Production from CO, CO.sub.2,
and H.sub.2 by Clostridium Ljungdahlii, K.M.O. Lundback et al, Presented at
Twelfth Symposium on Biotechnology for Fuels and Chemicals, Gatlinburg,
Tennessee, May 1990.
Clostridium Ljungdahlii Petc SP.Nov., A New Acetogenic, Gram -Positive,
Anaerobic Bacterium, R.S. Tanner and D. Yang, Abstracts of the 1990 Annual
Meeting of the American Society for Microbiology, No. R-21, p. 249.
Indirect Coal Liquification, GADDY, Technical Support, 1985.
Study of Gaseous Substrate Fermentations: Carbon Monoxide Conversion to
Acetate. 2. Continuous Culture, J.L. Vega, G.M. Antorrena, E.C. Clausen, and
J.L. Gaddy, Biotechnology and Bioengineering, vol. 34, Sep. 1989, pp. 785-793.
Dashekvich et al. Identification of a Carbon Monoxide -Metabolizing Bacterium
as a Strain of Rhodopseudomonas gelatinosa (Molisch) van Niel. International
Journal of Systematic Bacteriology, Apr. 1979, vol. 29, pp. 145-148.
Uffen, R.L. Anaerobic growth of Rhodopseudomonas species in the dark with
carbon monoxide as sole carbon and energy substrate. Proceedings of the
National Academy of Sciences. Sep. 1976, vol. 73, No. 9, pp. 3298-3302.
Stupperich et al. Carbon monoxide fixation into the carbonyl group of acetyl
coenzyme A during autotrophic growth of Methanobacterium. FEBS Letters,
Feb. 1983, vol. 152, No. 1, pp. 21-23.
O'Brien et al. Association of Hydrogen Metabolism with Unitrophic or
Mixotrophic Growth of Methanosarcina Barkeri on Carbon Monoxide, Journal of
Bacteriology. Apr. 1984, vol. 158, No. 1, pp. 373-375.
Miller et al. Oxidation of Hydrogen and Reduction of Methanol to Methane is the
Sole Energy Source for a Methanogen Isolated from Human Feces, Journal of
Bacteriology, Feb. 1983, vol. 153, No. 2, pp. 1051-1055.
Diekert et al. Carbon monoxide fixation into the Carboxyl group of acetate
during growth of Acetobacterium woodii on H.sub.2 and CO2. FEMS
Microbiology Letters, 1983, vol. 17, pp. 299-302.
Nakamura et al. Taxonomic Study of Bacillus coagulans Hammer 1915 with a
Proposal for Bacillus smithii sp. nov. International Journal of Systematic
Bacteriology. Jan. 1988, vol. 38, No. 1, pp. 63-73.
Kruger et al. Thermophilic Bacilli growing with carbon monoxide. Archives of
Mirobiology. Nov. 1984, vol. 139, No. 4, pp. 402-408.
Primary Examiner: Lilling; Herbert J.
Attorney, Agent or Firm: Howson and Howson
Goverment Interests
U.S. GOVERNMENT LICENSE RIGHTS
This invention was made with U.S. Government support under Department of Energy
Small Business Innovation Research Program Contract No. DE-FG05-90ER81057
awarded by the Department of Energy.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of Ser. No. 08/220,686, filed Mar. 31, 1994, now
abandoned.
Claims
We claim:
1. A biologically pure culture of the microorganism Bacillus smithii ERIH2 having all of
the identifying characteristics of ATCC No. 55404.
2. The culture according to claim 1, having the ability to produce hydrogen under
anaerobic conditions upon fermentation in an aqueous nutrient medium containing
synthesis gas as a substrate.
3. The culture according to claim 2 wherein said substrate is selected from the group
consisting essentially of CO, CO.sub.2, and H.sub.2.
4. The culture according to claim 1, having the ability to produce hydrogen under
anaerobic conditions in an aqueous nutrient medium comprising sources of carbon.
5. The culture according to claim 4 wherein said carbon source is a sugar.
6. The culture according to claim 1, said culture being rod -shaped, non-sporeforming,
gram -positive, and facultatively anaerobic.
7. The culture according to claim 1, having the ability to ferment glucose under anaerobic
conditions and produce formate, acetate and lactate.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a process for converting waste biomass to useful
products utilizing anaerobic bioconversion in at least one stage of the process and to a
biologically pure culture of an isolated anaerobic microorganism capable of producing
useful products from synthesis gas.
The U.S. currently consumes 3.6 trillion cubic feet (TCF) of hydrogen annually, with
worldwide consumption about three times this amount. The U.S. demand for hydrogen is
expected to grow 60percent, or 1.4 TCF, in the next five years. This growth is primarily
for refinery requirements to produce higher quality gasoline and to remove heteroatoms
from lower quality crude. In addition, large quantities of hydrogen will be required for
the production of alternative liquid fuels from coal, shale oil, or tar sands. The current
contract price for hydrogen delivered by pipeline on the Gulf Coast is about $1.85 per
MCF and is heavily dependent upon the price of natural gas. Further gas price increases
will raise hydrogen prices proportionately.
This nation has a severe shortage of liquid fuel, but an abundance of coal. Logically,
research has been directed toward developing technology for producing liquid fuels from
coal. Processes have been developed for direct coal liquefaction, as well as liquefaction
of synthesis gas by Fisher Tropsch reactions, methanol homologation, etc. (Hessley et al.,
1986; Payne, 1987).
The liquid fuels produced have atomic hydrogen to carbon ratios (H/C) of about two and
water is often a by-product, requiring additional hydrogen. Coal has a H/C ratio of, at
best, one. Consequently, production of liquid fuels from coal requires substantial
amounts (>50 percent) of added hydrogen.
The liquids from coal liquefaction, as well as from other fossil resources, such as
bitumen from tar sands or kerogen from oil shale, contain large fractions of heteroatom
compounds that must be removed before refining. These oxygen, sulfur and nitrogen
contaminants are removed by reaction with hydrogen. Therefore, hydrogen is a key
ingredient in the utilization of coal and other fossil energy reserves.
Most of the hydrogen produced throughout the world is made from synthesis gas. The
synthesis gas may be derived by reforming of natural gas or by gasification of coal.
Carbon monoxide in synthesis gas reacts with water to produce hydrogen by the water -
gas shift reaction:
CO+H.sub.2 0-.fwdarw.CO.sub.2 +H.sub.2 .DELTA.H=-9.8 kcal (1)
This slightly exothermic reaction is catalyzed by heterogeneous mixtures of metals such
as chromium, iron, zinc, copper, cobalt, etc. (Wender, 1987). The catalysts are
deactivated by sulfur, carbon deposition, and high temperature. Following the shift
reaction, the CO.sub.2 and other components may be removed by absorption and a pure
hydrogen product is obtained. Alternatively, the water -gas shift reaction may be used to
adjust the H.sub.2 composition in synthesis gas, for subsequent reaction.
In today's economy, the cost of hydrogen by catalytic processes is excessive, which
makes alternative liquid fuels uncompetitive. Consequently, coal conversion processes,
and tar sands and oil shale development, are severely impeded by a lack of low cost
hydrogen. An economical process for production of large quantities of hydrogen is
required for development of these alternative energy strategies.
Therefore, there is a need for an improved, simple and economical process for the
biological production of hydrogen.
SUMMARY OF THE INVENTION
In accordance with the present invention, a biological process is provided for converting
waste biomass to useful products by gasifying the biomass to produce synthesis gas and
converting the synthesis gas to a useful product or intermediate utilizing one or more
microorganisms capable of converting a synthesis gas substrate to one or more useful
products, such as hydrogen, acetic acid or ethanol.
In accordance with a particular embodiment of the present invention, waste biomass is
converted to synthesis gas containing carbon monoxide (CO) and the CO is converted to
hydrogen (H.sub.2) by an anaerobic microorganism ERIH2, Bacillus smithii ATCC No.
55404.
The first stage in the development of the present invention was to demonstrate the
technical feasibility of producing hydrogen by a unique biochemical route. The anaerobic
photosynthetic bacterium Rhodospirillum rubrum was used to convert CO and water to
hydrogen. Three tasks were performed: definition of the conditions of media, light, pH
and temperature to maximize bacterial growth and hydrogen production; preliminary
continuous reactor experiments to determine reaction rates and reactor volumes; and a
preliminary process design and economic evaluation from the preceding data.
As described in more detail later, the first stage objectives were satisfactorily achieved.
Stoichiometric yields of hydrogen have been obtained from CO with R. rubrum. Fast
growth was observed on synthesis gas only; however, growth was maximized with a
small amount of yeast extract at 30.degree. C. and pH 7. Intrinsic kinetic parameters have
been determined and show that fast hydrogen production rates are possible. Virtually
complete conversion was obtained with short retention times in the CSTR. The projected
economics show that hydrogen can be produced for $0.77 per MSCF including H.sub.2
separation, so that commercialization at this price would be assured. The technical and
economic feasibility of this technology was demonstrated.
The second stage of the present invention concentrated on defining the optimal culture
and bioreactor for hydrogen production. To ensure that the best possible system was
developed, cultures were screened for enzyme activity and hydrogen production.
Promising cultures were optimized for hydrogen yield and CO conversion. Bioreactors
that achieve high mass transfer rates, as well as high cell concentrations, were studied.
Immobilized cell reactors and trickle bed reactors are especially suited for this
application. Advanced bioreactor concepts such as solid-state fermentation, non -aqueous
fermentation, and high pressure fermentation were applied to these reactors to enhance
gas mass transport. Equivalent retention times of seconds are conceivable for this
technology. Process design and economic evaluations of the various alternatives were
used to guide the development of the present invention.
The third stage of development of the present invention involved the study of sources of
synthesis gas, gasification methods and apparatus, and synthesis gas compositions in
order to optimize an overall process of converting waste biomass, including coal,
municipal solid waste, sewage sludge, plastic, tires, agricultural and fisheries waste and
the like to useful products such as hydrogen, ethanol and acetic acid. The overall process
includes the steps of gasifying the waste biomass to produce synthesis gas, converting the
synthesis gas to the desired product or products using anaerobic gaseous -substrate
fermentation, then recovering the product or products.
A principal objective of the present invention is the provision of a process for producing
hydrogen from synthesis gas by anaerobic conversion.
Another object of the present invention is the provision of a biological process for
converting synthesis gas to useful products.
Yet another object of the present invention is the provision of a process for converting
waste biomass to useful products.
Still yet another object of the present invention is the provision of a commercially viable
process for producing hydrogen from waste biomass by gasification of the biomass to
produce synthesis gas, anaerobic bioconversion of the synthesis gas to hydrogen, and
recovery of the hydrogen.
Another object of the present invention is the provision of a biologically pure culture of
an isolated anaerobic microorganism Bacillus smithii, ERIH2, ATCC No. 55404.
Other objects and further scope of the applicability of the present invention will become
apparent from the detailed description to follow, taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 of the drawings is a schematic representation of a system and process for
converting waste biomass to useful products in accordance with the present invention;
FIGS. 2-4 are schematic illustrations of generic moving -bed, fluidized -bed, and
entrained -flow gasification reactors, respectively;
FIGS. 5-82 are graphical illustrations of the below -given relationships:
FIGS. 5-19 initial conditions: 1 atm, 100 rpm, 30.degree. C., various initial cell
concentrations.
FIG. 5 Effect of Temperature on R. rubrum ATCC 9791
FIG. 6 Performance of R. rubrum ATCC 9791 and 25903
FIG. 7 H.sub.2 Yield of R. rubrum ATCC 9791 and 25903
FIG. 8 Performance of R. rubrum ATCC 17032 and 25903
FIG. 9 H.sub.2 Yield of R. rubrum ATCC 17032 and 25093
FIG. 10 Performance of R. rubrum ATCC 19613 and 25903
FIG. 11 H.sub.2 Yield of R. rubrum ATCC 19613 and 25903
FIG. 12 Performance of R. rubrum ATCC 17031 and 25903
FIG. 13 H.sub.2 Yield of R. rubrum ATCC 17031 and 25903
FIG. 14 Performance of R. rubrum ATCC 17036 and 25903
FIG. 15 H.sub.2 Yield of R. rubrum ATCC 17036 and 25903
FIG. 16 Performance of R. rubrum ATCC 25852 and 25903
FIG. 17 H.sub.2 Yield of R. rubrum ATCC 25852 and 25903
FIG. 18 Performance of R. rubrum ATCC 27048 and 25903
FIG. 19 H.sub.2 Yield of R. rubrum ATCC 27048 and 25903
FIG. 20 Comparison of CO Consumption and H.sub.2 Production with R. rubrum strains
(Cell Conc. 0.5 g/L)
FIG. 21 Comparison of CO Consumption and H.sub.2 Production with R. rubrum strains
(Cell Conc. 0.57 g/L)
FIG. 22 Comparison of CO Consumption and H.sub.2 Production with R. rubrum strains
(Cell Conc. 0.54 g/L)
FIG. 23 Comparison of CO Consumption and H.sub.2 Production with R. rubrum strains
(Cell Conc. 0.4 g/L)
FIG. 24 Comparison of CO Consumption and H.sub.2 Production with R. rubrum strains
(Cell Conc. 0.45 g/L)
FIG. 25 CO consumption by R. rubrum and Isolate I
FIG. 26 H.sub.2 Production by R. rubrum and Isolate 1
FIG. 27 CO Consumption and H.sub.2 Production by Isolate 2
FIG. 28 CO Utilization/Methane Production by M. barkeri
FIG. 29 The Effect of CO Concentration on CO Consumption
FIG. 30 The Effect of CO Concentration on H.sub.2 Production
FIG. 31 The Effect of CO Concentration on Bacterial Growth
FIG. 32 H.sub.2 S Toxicity on R. rubrum ATCC 25903
FIG. 33 COS Toxicity on R. rubrum ATCC 25903
FIG. 34 The Effect of Methane on CO Consumption
FIG. 35 CO Conversion as a Function of Agitation in Continuous Culture with R. rubrum
ATCC 25903
FIG. 36 H.sub.2 Yield as a Function of Agitation in Continuous Culture with R. rubrum
ATCC 25903
FIG. 37 CO Conversion as a Function of Gas Retention Time for R. rubrum
FIG. 38 Performance of CSTR with Varying Liquid Retention Time (R. rubrum)
FIG. 39 Effect of Gas Retention Time on CO Conversion, 1000RPM
FIG. 40 The Effects of Agitation Rate and Gas Residence Time on CO Conversion in the
CSTR by ERIH2
FIG. 41 CO Conversion and H.sub.2 Yield by ERIH2 in the CSTR with Cell Recycle (2-
4 g/L glucose)
FIG. 42 Cell Growth (OD580) by ERIH2 in the CSTR with Cell Recycle (2-4 g/L
glucose)
FIG. 43 H.sub.2 Productivity of ERIH2 in the CSTR with Cell Recycle (2-4 g/L glucose)
FIG. 44 CO Conversion by ERIH2 in the CSTR with Cell Recycle (I g/L glucose)
FIG. 45 H.sub.2 Yield by ERIH2 in the CSTR with Cell Recycle (I g/L glucose)
FIG. 46 Optical Density Measurements for ERIH2 in the CSTR with Cell Recycle (1 g/L
glucose)
FIG. 47 Gas Retention Time Profile in the Immobilized Cell Reactor Using ERIH2
FIG. 48 CO Conversion in the Immobilized Cell Reactor Using ERIH2
FIG. 49 H.sub.2 Yield from CO in the Immobilized Cell Reactor with ERIH2
FIG. 50 CO Conversion in the Trickle Bed Reactor with ERIH2(2 g/L glucose)
FIG. 51 H.sub.2 productivity, Trickle Bed Reactor with ERIH2 (2g/L glucose)
FIG. 52 CO Conversion and H.sub.2 Production by ERIH2 in the High Pressure Parr
Reactor (0.9 g/L glucose)
FIG. 53 Optical Density and pH Measurements in the High Pressure Parr Reactor with
ERIH2 (0.9 g/L glucose)
FIG. 54 The Effect of Dextran on CO Consumption
FIG. 55 The Effect of Xantham Gum on CO Consumption
FIG. 56 The Effect of Triton N-42 on CO Consumption
FIG. 57 The Effect ofTWEEN-85.TM. detergent on CO Consumption
FIG. 58 The Effect of TRITON X-15.TM. detergent on CO Consumption
FIG. 59 The Effect of TERGITAL .TM. detergent on CO Consumption
FIG. 60 The Effect of TRITON N-IOLTM. detergent on CO Consumption
FIG. 61 The Effect of NONIDET P-40198 detergent on CO Consumption
FIG. 62 The Effect of TYLOXAPOL.TM. detergent on CO Consumption
FIG. 63 The Effect of Glycerol on CO Consumption
FIG. 64 The Effect of FC-40.TM. detergent on CO Consumption
FIG. 65 Determination of Mass Transfer Coefficient Kla/H Plot Using Dextron at 0.1 %
V. Concentration
FIG. 66 Determination of Mass Transfer Coefficient Kla/H Plot Using Xantham Gum at
0.25% V. Concentration
FIG. 67 Determination of Mass Transfer Coefficient Kla/H Plot Using Triton N-42 at
0.1 % V. Concentration
FIG. 68 Determination of Mass Transfer Coefficient Kla/H Plot Using TWEEN-85198
detergent at 0.1% V. Concentration
FIG. 69 Determination of Mass Transfer Coefficient Kla/H Plot Using TRITON X-
15.TM. detergent 0.1% V. Concentration
FIG. 70 Determination of Mass Transfer Coefficient Kla/H Plot Using TERGITOL.TM.
detergent at 0.1 % V. Concentration
FIG. 71 Determination of Mass Transfer Coefficient Kla/H Plot Using TRITON N-
I OLTM. detergent at 0.1% V. Concentration
FIG. 72 Determination of Mass Transfer Coefficient Kla/H Plot Using NONIDET P-
40.TM. detergent at 0.1 % V. Concentration
FIG. 73 Determination of Mass Transfer Coefficient Kla/H Plot Using
TYLOXAPOL.TM. detergent at 0.1% V. Concentration
FIG. 74 Determination of Mass Transfer Coefficient Kla/H Plot Using Glycerol at 10%
V. Concentration
FIG. 75 Determination of Mass Transfer Coefficient Kla/H Plot Using FC-40.TM.
detergent at 10% Concentration
FIG. 76 The Effect of Tyloxapol on CO Conversion by ERIH2 in the CSTR
FIG. 77 Effect of EMCOL CNP -I I O.TM. detergent on CO Conversion by ERIH2 in the
CSTR
FIG. 78 Gas Phase Partial Pressure Profiles for ERIH2 in Batch Culture
FIG. 79 Determination of Mass Transfer Coefficient in the Batch Bottle Experiments
FIG. 80 Liquid Phase CO Tension Profile for ERIH2 Obtained in Batch Culture
FIG. 81 Determination of Monod Relationship for ERIH2; and
FIG. 82 Typical Equilibrium Lines for Chemical and Physical Solvents.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Synthesis gases (syngas) consisting mainly of CO, H.sub.2, and CO.sub.2, may be
produced from carbonaceous ma terials according to the approximate reaction:
CH.sub.2 0+0.1250.sub.2 (+0.5N.sub.2)-.fwdarw.0.75CO+0.25CO.sub.2 +H.sub.2
Biomass Various biomass wastes are available for gasification, including paper,
municipal solid waste (MSW), tires, bagasse, sewage sludge, sawdust, rice hulls, plastic
paper -mill sludges, etc. (TABLES 1 and 2). Many of these wastes have a negative value
because of their disposal costs. Coal, of course, may also be gasified by similar
stoichiometry. The resultant gas composition is a function of the amount of air, or
oxygen, necessary to generate the heat for pyrolysis of the biomass waste. An av erage
synthesis gas composition is CO -30 percent, H.sub.2 -40 percent, CO.sub.2 -10 percent,
and N.sub.2 -20 percent. If oxygen is used, nitrogen is eliminated. Typically, synthesis
gas components will generally fall in these ranges: CO -10 to 50%, CO.sub.2 -8 to 50%,
H.sub.2 -10 to 40%, N.sub.2 -0.5 to 60%, CH.sub.4 -0.01 to 10%, and S gas compounds -
0.02 to 10%.
In accordance with the present invention, carbon monoxide may be converted into
hydrogen by certain anaerobic bacteria according to:
CO+H.sub.2 0-.fwdarw.H.sub.2 +CO.sub.2 (3)
The performance of these bacteria is summarized later; however, very fast reaction rates
have been achieved. Also, these bacteria are not sensitive to sulfur and, thus, raw
svnthesis Pas can he used as the source of CO.
the bioreactor along with any nitrogen as a vent gas 42.
The vent gas 42 is treated by purification unit or system 20 which separates the hydrogen
44 from the other gas components 46. The hydrogen output 44 of purification unit 20 is
compressed by compressor 22 to form a hydrogen product 48. Thus is described a system
for converting biomass waste 24 into a useful product such as hydrogen 48.
The bioreactor 18 is operated at the same pressure as the gasifier 12. The hydrogen
product 48 can be introduced into a pipeline or delivered to a customer or customers.
The biological process offers the advantages of high efficiency and low capital and
operating cost. The microorganisms in the bioreactor 18 use only a small fraction of the
syngas substrate 38 for growth and energy, therefore high product yields (98 percent) are
obtained. The biocatalyst is automatically regenerated by slow growth of the bacteria,
which are not inhibited by synthesis gas components. Biological processes are
compatible with the environment and the utilization of wastes is environmentally
beneficial.
The primary disadvantage of biological processes is generally the slow reaction rates.
Cultures and bioreactors for this reaction have been studied extensively and are described
later. Retention times of seconds have been achieved for the biocatalytic reaction, which
makes this process competitive with catalytic processes.
MICROBIOLOGICAL PRODUCTION OF HYDROGEN FROM CARBON
MONOXIDE
There are a large number of microorganisms that utilize CO and a few of these produce
H.sub.2 according to Equation (3). Many aerobic bacteria can grow on CO and O.sub.2
as the sole carbon and energy sources (Hegemann, 1980; Uffen, 1981; Meyer and
Schlegel, 1983). These organisms contain a membrane -associated carbon monoxide
oxidase which catalyzes the irreversible oxidation of carbon monoxide in the presence of
electron acceptors such as methylene blue. The aerobic enzyme contains molybdenum
and is stable in the presence of molecular oxygen. Among the aerobic CO -oxidizing
microorganisms, the carboxydobacteria are probably the most important and are
recognized to be a major factor in the removal of carbon monoxide from the atmosphere
(Spratt and Hubbard, 1981).
The bacterium Rhodospirillum rubrum has been shown to oxidize CO to CO.sub.2 and
produce stoichiometric amounts of H.sub.2 from water nonphotosynthetically (Vega et
al., 1988a). The cell growth, however, requires light and was not previously thought to
require CO, but to utilize other organic carbon sources (Gest et al., 1950). Results from
the first stage of development of the present invention have shown that R. rubrum can
grow on the components of synthesis gas as the sole carbon source.
Recent research also indicates that CO.sub.2 fixation can occur with R. rubrum. Quayle
and Pfenning (1975) reported that several photosynthetic bacteria, including R. rubrum,
are able to use the ribulose biphosphate pathway for CO.sub.2 assimilation. R. rubrum
can also grow autotrophically with H.sub.2 (Anderson and Fuller, 1967). The primary
product of autotrophic CO.sub.2 fixation in R. rubrum is 3 -PGA (Fuller, 1978). The path
of carbon in R. rubrum during autotrophic metabolism involves CO2 fixation via the
Calvin cycle and numerous ancillary carboxylations. Thus, coal gas can provide the
components necessary for cell growth.
A basal medium, containing NH.sub.4 Cl as the nitrogen source and acetate as a carbon
source, has been recommended for growth of R. rubrum (Gest et al., 1950). Light is also
needed as an energy source for growth. Small amounts of oxygen in the gas phase are not
lethal to the bacteria. This bacterium can also tolerate high concentrations of H.sub.2 S
and COS (Vega et al., 1989a).
Recently, it has been found that other species have the potential to carry out the water -
gas shift reaction. Certain CO utilizing methanogens have been found to produce H.sub.2
from CO when methane formation is inhibited. Daniels et al. (1977) studied the CO
oxidation of Methanobacterium thermoautotrophicum. Cell suspensions, previously
frozen at-20.degree. C., produced stoichiometric H.sub.2 and CO.sub.2 for every mole of
CO used. Only small amounts of CH.sub.4 were formed. In the presence of chloroform,
the formation of CH.sub.4 was completely eliminated, with only H.sub.2 and CO.sub.2
as the end products.
O'Brien et al. (1984) reported that H.sub.2 was produced when CO -adapted strains of
Methanosarcina barkeri grow with more than 20percent CO as the sole carbon source and
energy source, while H.sub.2 was consumed when the CO concentration was below 20
percent. Bhatnagar (1987) reported that the purified CO -dehydrogenase from M. barkeri
has H.sub.2 production activity of 278.9 mmole H.sub.2 /min mg protein when 2 mM
methyl viogen and 1 atm CO is supplied. Bott and Thauer (1989) reported that cell
suspensions of acetate -grown M. barkeri catalyze the stoichiometric conversion of free
CO to CO.sub.2 and H.sub.2 when methane formation from the products is inhibited.
Martin et al. (1983) observed the carbon monoxide -dependent evolution of H.sub.2 by
Clostridium thermoaceticum. Hydrogen was formed when C. thermoaceticum was
cultivated heterotrophically on dextrose under a carbon monoxide gas phase. Resting
cells from the CO -grown culture also formed H.sub.2 when under CO with dextrose. In
contrast, when cultivated under CO.sub.2 only minimal levels of H.sub.2 were detected.
It was suggested that the mechanism involved some of the reducing equivalents
generated by CO dehydrogenase (CO+H.sub.2 0-.fwdarw.CO.sub.2 +2H.sup.++2e.sup.-
) to be converted to H.sub.2 by subsequent action of hydrogenase. However, H.sub.2 was
not generated in the absence of dextrose, and it was not certain that H.sub.2 was derived
by the water -gas shift reaction.
One objective of the present invention was to determine the feasibility of the biological
production of hydrogen from the water -gas shift reaction with R. rubrum. This objective
was achieved by successfully enhancing culture performance and continuous reactor
performance.
Stoichiometric yields of hydrogen were obtained from CO by R. rubrum ATCC strain
25903. Fast reaction rates were achieved in batch and continuous culture. R. rubrum can
grow with coal gas as the sole carbon source, but small quantities of yeast extract were
required to enhance growth rates. The optimal pH and temperature to maximize the
growth and hydrogen production for R rubrum are 7.degree. and 30.degree. C.,
respectively. A light intensity of 1500 lux promotes cell growth, but light is not required
for hydrogen production. Therefore, the synthesis gas bioreactor does not require a light
source. The intrinsic kinetic parameters have been defined and indicate that fast rates in
continuous culture, without substrate inhibition, are possible.
The results of experiments to define reaction rates in continuous culture show that
retention times of less than 2 hours give virtually complete conversion of CO. The
reaction is mass transfer limited and increasing the agitation rate improves the
conversion. Mass transfer rates of 42 mmole/hr-L-atm have been achieved in the CSTR.
The high conversions at short retention times and high mass transfer rates establish the
technical feasibility of this process.
The purpose of the second stage of development of the present invention was to define
the optimal culture and bioreactor system to maximize the yield and production of
hydrogen from synthesis gas. The tasks performed in order to satisfy this objective were:
1. Culture Screening/Development
2. Continuous Bioreactor Studies
3. Advanced Bioreactor Concepts
4. Bioreactor Modeling/Scale-up The following description summarizes the research
effort and demonstrates the technical and economic feasibility of H.sub.2 production
from synthesis gas with a composition representative of that from coal.
The objective of culture screening and development was two -fold: first, to screen all
known shift conversion microorganisms to measure optimal performance and to select
those with the best yields, rates, CO and sulfur (S) tolerances, and fastest growth with
minimal nutrient and light requirements; and second, manipulation of the enzymatic
pathways to further enhance performance. Culture performance was best judged on the
basis of hydrogen production rate and yield. While R. rubnrrn was shown to give fast
rates of growth and hydrogen production, there was no assurance that another shift
conversion organism was not superior. However, rates and yields for other shift
conversion organisms had not been determined so that a comparison could be made.
Other important factors in selecting the best organism are growth rate, growth conditions
(nutrients, light, pH, temperature), and tolerance to CO and sulfur gases. Therefore, all
known shift conversion organisms were screened with several of the best organisms
selected for subsequent parameter optimization. Tolerance to toxic substances was
determined and the cultures manipulated to maximize enzyme activity. The best
organism was then selected for continuous bioreactor studies.
There are five bacteria that are known to carry out the water -gas shift reaction: R.
rubrum, Rhodopseudomonas gelatinosa, Methanosarcina barkeri, M.
thermoautotrophicum and Clostridium thermoaceticum. However, there are several
strains of each of these bacteria that may perform differently. For example, the American
Type Culture Collection (ATCC) has 12 strains of R. rubrum and three strains of R.
gelatinosa. Some strains of R. rubrum can grow in the dark (Uffen, 1971). Strains of R.
gelatinosa have been isolated that grow without light and with CO as the sole carbon and
energy source (Uffen, 1976; Dashekvicz and Uffen, 1979). In addition, other
Rhodospirellaceae (members of Rhodopseudomonas, Rhodosprillum, Rhodocyclus, and
Rhodomicrobium) may have the capability of producing hydrogen.
Each of these bacteria and the various strains were studied. An initial screening was
conducted to select those bacteria that have promise. These screening experiments were
conducted in batch reactors, using 150 ml serum bottles. All the shift conversion bacteria
are anaerobes, and the anaerobic methods of Hungate (1969), as modified by Bryant
(1972) and Balch and Wolfe (1976), were utilized.
Screening studies were conducted with all 12 strains of R. rubrum. The screening process
included first activation of the culture, then adaptation to a synthesis gas atmosphere, and
finally comparison of the CO consumption rate with other strains at the same cell
concentration. Culture activation was performed in 25 ml roll tubes with 10 ml medium
(Table 23) under 80percent N.sub.2 and 20 percent CO.sub.2 atmosphere. The medium
and the incubation temperature for the culture activation were prepared according to the
ATCC recommendation for each strain. In all cases, illumination was supplied at 1800 to
1900 lux with a lighted shaking incubator.
Once the culture had grown in the roll tubes, the bacteria were inoculated into 150 ml
serum bottles, containing 45 ml of the R. rubrum medium. The gas space was purged
with synthesis gas, composed of 20.8 percent H.sub.2, 64.34 percent CO, 4.06 percent
CH.sub.4 and 10.8 percent CO.sub.2. More synthesis gas was supplied by regassing
periodically as needed during the adaptation stage.
After the culture was adapted to synthesis gas and had consistent growth, the screening
experiments were initiated. A relationship between cell concentration (dry weight) and
optical density (482 nm wavelength) was obtained with R. rubrum ATCC strain 25903 as
the control. Both strains were inoculated into two separate 150 ml serum bottles with 45
ml of fresh medium for each strain to form the same initial cell concentration. The
inoculated bottles were then purged with one atmosphere of synthesis gas and incubated
at 100 rpm in the shaker incubator with light at 1800-1900 lux. The gas compositions
were periodically sampled and analyzed by gas chromatography to monitor the CO
consumption rates and H.sub.2 production rates. The performance of the strain was then
based upon a comparison of the CO consumption rates and the H.sub.2 yield from CO.
The specific CO uptake rates and culture growth rates were also calculated.
ATCC R. rubrum strains, 9791, 17031, 17032, 17036, 19613, 25852, and 27048 were
compared with ATCC 25903 for the ability to utilize synthesis gas to produce H.sub.2.
The literature recommends that all the strains, except strain 9791, have an optimum
incubation temperature of 30.degree. C. However, as is shown in FIG. 5, CO
consumption and H.sub.2 production are not significantly affected by temperature
between the optimum recommended temperatures of 26.degree. C. for strain 9791 and
30.degree. C. used for all other strains. Thus, the screenings were all conducted at
30.degree. C.
Among the R. rubrum strains studied, ATCC 9791, 17032, and 19613 showed higher CO
uptake rates than strain 25903. Table 4shows a summary of the comparison. Since strain
25903 was used as the control for comparison in all of the experiments, variable
performance was observed for this culture and the maximum and minimum values are
listed. Strains 9791, 17032, and 19613 showed performance superior to the best case for
strain 25903. The CO consumption rates of strain 17036 and 25852 were close to the
minimum level of strain 25903. The performances of strains 17031 and 27048 were much
worse than the rest of the group.
FIG. 6 shows CO consumption and H.sub.2 production as a function of time for strains
9791 and 25903. FIG. 7 shows the hydrogen yields for these bacteria. As is shown in
these figures, strain 9791 is superior in converting CO to H.sub.2. Not only does strain
9791 consume CO faster than strain 25903, but it also gives a higher H.sub.2 yield (90
percent compared to 80 percent) As is noted in FIG. 6, strain 9791 had a maximum CO
consumption rate nearly three times higher than strain 25903 (27.9 vs. 9.6mmole/g hr).
FIGS. 8 and 9 show the comparisons for strains 17032 and 25903. Strain 17032 had a
maximum CO consumption rate of 22.5mmole/g hr, about double that of the 11/3
mmole/g hr observed in strain 25903. However, strain 25903 had a slightly better H.sub.2
yield, 85 percent vs. 82 percent.
FIG. 10 shows the CO consumption and H.sub.2 production for strains 19613 and 25903.
Even though the overall CO consumption is very close in this comparison, the initial cell
concentration of strain 19613 was only about 70 percent of that for strain 25903. Thus,
the specific performance of strain 19613 is superior. The maximum CO consumption
rates were 22.2 vs. 16mmole/g hr, while the average for the first five hours gave CO
uptake rates of 220.1 vs. 12.8 mmole/g hr. FIG. 1 I shows the comparison of the H.sub.2
yield of these two strains. Strain 19613gave higher yields, 80 percent vs. 70 percent.
FIGS. 12-19 give comparisons of CO consumption, H.sub.2 production, and H.sub.2
yield for the other bacteria. As is noted, these strains are inferior to R. rubrum 25903.
Strains 9791, 19613, and 17032 were selected for further study. Each of these strains has
a fast CO utilization rate and high yield. Strain 25903 was also studied further because of
its fast growth rate.
To help identify the best R. rubrum strain, the specific CO consumption rates and the
H.sub.2 production yields were compared at five inoculum levels. FIGS. 20-24 show
both the CO consumption and H.sub.2 production in these five screening experiments. As
is shown in these figures, there is no significant difference in the performance of these
four strains. The CO consumption rate was in the range of 15 to 16.1 mmole/g hr, and the
H.sub.2 yield was in the range of 77 to 81 percent. Table 4 summarizes the data of these
experiments. The average specific consumption rate was 15.6 mmole/g hr and the
average yield was 79 percent.
Three strains of Rhodopseudomonas gelatinosa, ATCC 17011, 17013 and 17014, were
obtained from ATCC. These three bacteria grow well on ATCC medium. However, no
sign of CO utilization was observed with any of these strains under either lighted or dark
conditions. According to Dashekvicz and Uffen (1979), strain 17011 is the only strain in
the ATCC collection that exhibits CO dependent growth in the dark. CO adaptation of
these strains was attempted by adding supplemental trypticase to replace yeast extract, as
recommended by Uffen (1976) for the potential growth on CO. However, CO utilization
was still poor such that R. gelatinosa was not considered further.
Methanosarcina barkeri was activated with an atmosphere of 80 percent H.sub.2 and 20
percent CO.sub.2. Preliminary data indicated that this culture utilizes CO only at low CO
partial pressures (0.15 atm). FIG. 25 shows that H.sub.2, CO and CH.sub.4 composition
changes during a typical run. The initial gas composition was 14.3 percent H.sub.2, 12.7
percent CO, and 5.02 percent CO.sub.2 with the balance N.sub.2. Since no methane
inhibitor was provided, all H.sub.2, including the gas produced from CO, was converted
into CH.sub.4. As is shown in FIG. 25, CH.sub.4 formation continued after all the
H.sub.2 had been consumed. This phenomena indicates that the water -gas shift reaction
does take place in this culture.
In addition to R. rubrum and other cultures from ATCC, experiments were conducted to
isolate cultures from nature. An enrichment labeled ERIH2 was obtained from these
isolations. The ERIH2 isolate did not require light for growth and hydrogen production,
and also had a much faster CO consumption rate. FIGS. 26 and 27 show comparisons of
the CO consumption and H.sub.2 production rates for R. rubrum and isolate ERIH2. The
new isolate completely consumes the CO in about two hours while R. rubrum requires
more than eight hours. The H.sub.2 yield of the isolate ERIH2 is also very high. FIG. 28
shows the hydrogen production for isolate ERIH2 which is near 100 percent.
The new hydrogen -producing isolate ERIH2, which consumes CO rapidly and gives high
hydrogen yields, was thought to be a new bacterial strain. The isolate was purified and
sent to a microbiological laboratory for identification. Taxonomical studies were
performed to determine the genus of the bacteria. ERIH2 was determined to be a new
species of Bacillus and, more particularly, a new strain of Bacillus smithii by 16S rRNA
sequencing and a partial phenotypic characterization and was deposited with the
American Type Culture Collection, 12301 Parklawn Drive, Rockville, Maryland Md.
20252, on or about Mar. 18, 1993, with ATCC Designation 55404. The anaerobic strain
ERIH2 was characterized as a gram -positive rod, that frequently produces distorted
cells,and is non -spore forming, facultatively anaerobic, catalase positive, oxidase
negative, methyl red positive, Voges -Proskauer negative, starch negative. It ferments
glucose, producing formate, acetate and lactate, temperature optimum 50.degree. C.,
range 35-65.degree. C. Because of the obvious benefits in using ERIH2 (higher yields, no
light requirements, faster rates), it was used in the bulk of the remaining development of
the invention.
As was discussed previously, the bacterium ERIH2 has been shown to be very effective
in producing H.sub.2 and CO.sub.2 from CO and water by the biological water -gas shift
reaction. The specific CO uptake rate of ERIH.sub.2 is nearly 20 times the value shown
by R. rubrum in batch culture. However, ERIH2 suffers from poor growth rates, which
limits the global rate of CO uptake. An experimental program was thus initiated to
stimulate the growth of ERIH.sub.2 through the use of growth supplements. The results
of initial growth stimulation studies are shown below.
The growth of ERIH2 on various substrates was studied. Amino acids, asparagine and
several sugars were tested as growth and energy sources. Table 5 shows the cell
concentration changes with the addition of 2 g/L sugars. As is noted, nearly all of the
sugars are able to support a minimal level of growth. However, only galactose, glucose,
mannose, rhamnose and xylose can generate cell concentrations higher than 0.4. Also, for
most of the sugars, the cell concentration was reduced after day 2, and only galactose and
ribose gave continuous growth into the third day.
Corn steep liquor as a supplement to glucose was also investigated. Cell concentration
results from batch studies using glucose plus corn steep liquor as the growth substrate are
shown in Table 6. In addition to these carbon sources, the medium contained vitamins,
minerals, salts, trypticase and yeast extract. As is noted in Table 6, the addition of corn
steep liquor enhanced the cell concentration over glucose alone. However, the increase in
cell concentration was not large enough to justify the addition of the additional substrate.
It is also interesting to note in Table 6 that the impact of an additional 2 g/L of glucose on
cell concentration was not immediate, but seen after 22 hr of incubation.
Glucose and galactose were selected for further growth studies, since glucose is the
cheapest sugar and galactose has shown the fastest growth rates. In the second
experiments, 5 g/L of sugars was used. Table 7 shows the results of growth and pH
change. Both sugars supported growth to high levels within two days, with an
accompanying reduction in pH, due to acid production. However, when the pH dropped
below 5.5, the culture lost its ability to perfornt the water -gas shift reaction. As will be
shown in the CSTR studies, the reduction in pH due to growth on glucose can be readily
avoided by pH control inside the continuous reactor.
ERIH2 was next grown in batch culture on basal medium with 1 g/L yeast extract and I
g/L trypticase, supplemented with 0.75and 1.5 g/L glucose at 50.degree. C. and pH 6.9.
Samples were removed periodically and checked for pH, cell concentration, ammonia
production and glucose consumption.
Tables 8 and 9 show the results from this preliminary study. As is noted, ERIH2 grew
rapidly during the first 8 hours of incubation, with the cell concentration increasing by a
factor of 3.5-10. Glucose was consumed slowly during this period, with a significant
amount of ammonia produced. After this initial 8hours, glucose was consumed at a faster
rate and ammonia production continued. The cell concentration continued to increase in
one bottle, but fell in the other bottles, perhaps due to pH decreases.
These results indicate that ERIH2 grew mainly on trypticase and yeast extract during the
first 8 hours of incubation. The continued production of ammonia after 8 hours of
incubation indicates that ERIH2 cannot ferment glucose fast enough to couple all of the
amino acids from trypticase and yeast extract into cell protein. Glucose transport across
the cell membrane could thus be the growth limiting step. Additional sugars (lactose,
sucrose, fructose, galactose) were tested next for their ability to enhance growth.
Based upon the encouraging results presented in Tables 8 and 9, an intensive study was
performed to maximize the growth of ERIH2 in the presence of various nutrients.
Nutrient supplements such as lactose, mixed vitamins, asparagene and aspartic acid did
not appreciably affect growth. However, the use of high concentration of glucose,
trypticase and yeast extract resulted in significantly higher cell concentrations. The
feeding of 25g/L glucose, 20 g/L yeast extract and 5 g/L trypticase yielded a cell
concentration of 5.0 (see Table 10). Thus, high cell concentrations are indeed possible
with ERIH2 when using rich media.
Potential toxic compounds in synthesis gas include CO, H.sub.2 S, COS and trace
quantities of hydrocarbons. The effects of these toxic compounds on R. rubrum were
studied in batch experiments. The toxicity studies were conducted under optimal culture
conditions of 30.degree. C., pH 7, and a light intensity of 1500 lux, with various toxic gas
partial pressures.
Even though CO is the major substrate for the water gas -shift reaction, CO has also been
reported to be slightly toxic to R. rubrum. In this study, CO partial pressures of 0.8to 1.4
atm were provided. FIGS. 29 and 30 show CO consumption and H.sub.2 production, and
FIG. 31 shows the cell growth for these studies. As is noted in FIGS. 29-31, neither CO
consumption, nor H.sub.2 yield were appreciably affected by CO partial pressures up to
1.4 atm. Similarly, cell growth was not affected by CO partial pressures up to 1.4 atm.
Studies were also conducted with 0.009 to 0.045 atm H.sub.2 S and COS, the expected
concentration range for synthesis gas from high sulfur coal. FIGS. 32 and 33 show the
cell growth with a sulfur gas environment, without resupply of synthesis gas. As H.sub.2
S was added in increasing amounts, cell growth was slowed for the first 30 hours. This
result indicates that H.sub.2 S inhibits the initial growth with synthesis gas. However,
cell growth was enhanced by the addition of higher concentrations of H.sub.2 S after
30hours. The initial charge of synthesis gas was completely utilized in the first 30 hours;
thus, the growth was supported either from H.sub.2 or yeast extract. For the COS study,
there was no difference in growth in the first 10 hours. However, the growth after 10
hours was impaired by the addition of COS.
The effect of trace hydrocarbons on ERIH2 has been studied using methane gas. FIG. 34
shows the effect of 0 to 17 percent of methane on CO consumption. As is shown in FIG.
34, CO utilization by ERIH2 was not affected by the presence of methane.
The R. rubrum cultures were manipulated to enhance the H.sub.2 production. The
manipulation of the enzyme pathways is a factor in improving culture performance. The
enzymes involved in the biological shift conversion reaction include CO -dehydrogenase,
hydrogenase and/or nitrogenase. Hydrogen production depends on the presence of certain
metals; for example, carbon monoxide dehydrogenase from R. rubrum has been
characterized as a nickel, zinc, iron -sulfur protein. Enhancement of ERIH2 has been by
continued culture transfer.
Continuous stirred tank reactor (CSTR) studies with R. rubrum were conducted in a 2.5 L
New Brunswick BioFlo IIc fermenter. This fermenter has controlled temperature,
agitation, medium (Table 21) flow rate, and pH. The pH was monitored but not
controlled in this study since there was no significant pH change involved. The gaseous
substrate was manually controlled by a gas flow meter. Light was supplied for growth of
R. rubrumby direct illumination to the fermenter and/or by recycling a liquid stream
through an illuminated plastic vessel. A 40 watt tungsten bulb was placed inside the
center of the vessel and cooling water was circulated inside to absorb the heat from the
bulb. This lighted device was used to simulate the lighting system in a commercial size
reactor. The illumination was controlled by the flow rate of the recycled liquid stream.
FIG. 35 shows the CO conversion as a function of agitation rate for R. rubrum. The
operating conditions included a 2.8 hr gas retention time, 8.6 day medium retention time
(1800 ml culture), and steady state cell density of 2.5 g/L. As is shown in FIG. 35, the
CO conversion increased from 50 to 90 percent as the agitation rate increased from 200
to 600 rpm. Further increases in the agitation rate above 600 rpm did not further enhance
CO conversion. This phenomena indicates that the reaction is no longer mass transfer
limited. FIG. 36 shows the H.sub.2 yield as a function of agitation rate for R. rubrum in
the CSTR. As expected, the yield was not affected by the agitation rate, and remained at
about 80 percent.
FIG. 37 shows the CO conversion and R. rubrum as a function of gas retention time with
an agitation rate of 1000 rpm and an 8.6 day medium retention time. The conversion
increased from 50 percent to 90 percent as the gas retention time increased from 0.5 hr to
3 hr.
FIG. 38 shows the CO conversion and R. rubrum cell concentration with varying medium
retention time. The liquid retention time was controlled at 7, 3, and 1.7 days with the
agitation rate at 1000 rpm and a gas retention time of 1 hr. As the average CO conversion
was 75, 80, and 70 percent for 7, 3,and 1.7 days liquid retention times, respectively. The
cell concentration reduced from 2.5 g/L to 1.5 g/L when the liquid flow rate was
increased and the retention time was reduced to 1.7days retention time.
FIG. 39 shows a comparison of the effect of gas retention time on the CO conversion for
R. rubrum and two ERIH2 enrichments (Isolates 1 and 2). The study was conducted at
1000 rpm, with semi -batch liquid for both ERIH2 enrichments. Table 11 shows the
conversion for 10, 20, 30, 45, 60, and 90 minutes gas retention time. Obviously both
enrichments converted CO much faster than R. rubrum. Isolate 2 shows slightly better
performance in this preliminary study. The only problem with the enrichments is the very
slow growth, especially for Isolate 1.In these experiments, the optical density for Isolate
1 was only about 0.2, much less than the 0.6 for Isolate 2 and the 3.5 for R. rubrum.
Improvement of growth rates of the isolates will significantly improve performance.
Experiments were continued with the ERIH2 isolates in the CSTR. To minimize the
required reactor volume of the CSTR, the cell concentration was maximized. The
addition of glucose stimulated growth; however, the reduction in pH from subsequent
acid production significantly inhibited the gas utilization. Thus, pH control is essential in
successful operation of the CSTR. The chemostat was supplied with 2 g/L glucose in the
medium (Table 22) with a liquid retention time of 150 hr. A 1/4horsepower agitator was
used in this study. The effect of agitation rate with a 10 to 20 minute gas retention time
was studied. Table 12 summarizes the steady state CO conversion in this study. FIG. 40
shows CO conversion as a function of agitation and gas retention time. The H.sub.2
yields were from 90 to 95 percent in these runs. As expected, higher agitation rates and
longer gas retention times increased the conversion. The effect of agitation is significant
and shows the mass transfer limitations of the fermentation. A doubling of agitation rate
from 400 to 800 rpm doubles the conversion. Further increases do not have such a
pronounced effect, however.
The major problem encountered in operating a CSTR with strain ERIH2 is the inability to
maintain high cell concentrations inside the reactor. High cell densities typically translate
into high reaction rates, and thereby minimize reactor volume for a given gas retention
time. This problem was attacked by utilizing various concentrations of glucose as the
substrate for growth and by employing cell recycle. Cell recycle allows a higher
concentration of cells inside the reactor by separating the cells from the effluent and
returning them to the reactor. For example, the liquid effluent from the reactor is passed
to a centrifuge, hollow fiber membrane, or other filtration device to separate out
microorganisms that are entrained. These microorganisms are returned to the bioreactor
18 to increase the microorganism concentration. In accordance with a particular example,
the culture broth from the bioreactor is recycled through a cross-flow hollow fiber
module by a peristaltic pump. The recycling rate is about 80-100 mL/min. The hollow
fiber module has the following characteristics; the surface area is 0.35 ft.sup.2, the pore
size is 0.2 .mu. and the lumen diameter is 1 mm. The permeate from the fiber module is
pumped to a storage tank. The culture cells from the fiber module are returned to the
bioreactor.
In accordance with another example, a bench scale system operating with a CSTR and
the anaerobic bacteria ERIH2, consists of a New Brunswick Scientific Bioflow IIc
fermenter, a hollow fiber membrane unit for cell recycle, and extraction and distillation
columns. Nutrient mixture is fed into the bioreactor at a rate of 3.2 cubic centimeters per
minute. Capacity of the reactor is 2.5 liters, within which a constant fluid level of 1.5
liters is maintained. The fluid is agitated at variable rates of up to 1000 revolutions per
minute with syngas introduced at a rate of approximately 500 cubic centimeters per
minute. The syngas feed is vaned with its uptake by the bacteria, which was in tum a
function of the cell density. The liquid from the bioreactor is passed to the hollow fiber
membrane at a rate of 55 to 70 milliliters per minute. From the hollow fiber membrane,
permeate is gathered at a rate of 1 to 15 milliliters per minute. Culture cells and liquid is
returned to the fermenter at a rate of 40 to 69 milliliters per minute.
FIGS. 41-43 show the performance of strain ERIH2 in the CSTR with cell recycle by
plotting CO conversion, H.sub.2 yield, optical density as a measure of cell concentration
and reactor productivity as a function of time for various conditions in the reactor. The
reactor was initially operated as a CSTR without recycle using 2 g/L glucose as the
carbon source for growth. The gas retention time was 60 min at an agitation rate of 800
rpm. Cell recycle began after about 50 hrs of operation. Under these conditions, the
steady state CO conversion was about 85 percent, the H.sub.2 yield was 90-95 percent
(FIG. 40), the cell concentration was 0.24 g/L (O.D.=0.3) (FIG. 41) and the H.sub.2
productivity was 20 mmole/L.hr (FIG. 42).
Several changes were made over the next 300 hr while still utilizing 2 g/L glucose. The
agitation rate was changed to 100rpm at t=270 hr, and the gas retention time was lowered
to 18 min at t=300 hr. During each of these changes the CO conversion and H.sub.2 yield
remained constant (FIG. 47), while the cell density steadily increased (FIG. 42). The
optical density at 400 hr with a 15 min gas retention time was 0.7, over three times the
initial value. The productivity also increased, reaching 50-60mmole/L.hr. (FIG. 43).
When the glucose concentration was then raised to 4 g/L, the CO conversion was about
90 percent, the H.sub.2 yield was 90-100 percent, the cell density was nearly 0.8 and the
H.sub.2 productivity was 80 mmole/L.hr.
Based upon the success shown in FIGS. 41-43 with increasing glucose concentration, the
concentration of glucose was further increased to 10 g/L. A tabulation of steady state data
at this glucose concentration is shown in Table 13. The liquid dilution rate throughout the
study was 0.026 hr.sup.-1. As is noted in the table, the CO conversion decreased with gas
retention time, ranging from 85 percent at a 21.6 min retention time to 79 percent at an
8.1 min retention time. The H.sub.2 yield was 80-90 percent and the cell density was
approximately 2.4(0.D.=3.0). The H.sub.2 productivity increased with decreasing gas
retention time, reaching a maximum of 134 mmole/L.hr. When the glucose concentration
was again lowered to 1.0 g/L, the steady state CO conversion was 85 percent (FIG. 44),
the H.sub.2 yield was 100 percent (FIG. 45) and the cell density was 2.4 (FIG. 46). These
latter measurements were obtained at a 21.6 min gas retention time, a 0.026 hr.sup.-1
liquid dilution rate and 900 rpm.
It is interesting to note that the steady state conversions, yields and optical densities when
using either 1 g/L or 10 g/L glucose were the same. The cell concentrations obtained in
the CSTR/cell recycle system with 10 g/L glucose can apparently be viably sustained for
long periods of time with the aid of cell recycle. A lower glucose feed concentration is
thus possible.
The CSTR was operated without cell recycle in an effort to determine the effect of
certain variables on the yield of cells from glucose. The reactor was first operated at a
glucose concentration of 2 g/L, while varying the gas retention time and dilution rate.
Table 14 shows preliminary results from this study. As is noted, the optical density is
affected by increasing dilution rate, while the gas retention time affects CO conversion.
Experiments have been conducted with ERIH2 cells cross-linked to Ca -alginate to enable
operating temperatures of 50.degree. C. The culture was first centrifuged at 5000 rpm for
15minutes and the concentrated culture was washed with 35 ml of 0.9percent anaerobic
NaCl solution. The concentrated culture solution was then mixed with an equal volume
of 4 percent Na -alginate inside an anaerobic chamber. Calcium carbonate (0.79g) and
glueanolactone (0.7 g) were added to the solution to form concentrated cell/gel beads.
The cell/gel beads were maintained inside the anaerobic chamber for a few hours to dry
and then placed into the column reactor. In the initial test, no solid support was provided.
Without support, the beads deformed with the pressure of the fluid so that the column
became plugged and even distribution of fluid could not be maintained. Therefore,
subsequent experiments used sterilized 6 nun porcelain berl saddles as the support for the
gel. With the gel on the surface of the saddles, the porosity of the column was maintained
and flow problems were reduced. Operation of the column was satisfactory, although the
volume of the support greatly increased the required retention time for a given
conversion.
Finally, the performance of ERIH2 was demonstrated in an immobilized cell column
reactor (ICR) packed with 4-12 mesh activated carbon. The total column volume was 635
mL and the column void volume was 265 mL. The temperature of the system was held
constant at 50.degree. C. and the liquid flow rate to the system was maintained at 0.4
mUmin. The gas retention time (based on void volume), shown in FIG. 47 as a function
of operating time, was generally 5-10 hr, except during start-up and during a brief
interruption in operation at t=1200 hr. The glucose concentration fed to the reactor to
maintain growth was 6 g/L during the first 1000 hr of operation, was increased to 10 g/L
during the next 200 hr, was decreased to 2 g/L for a short recovery period and was finally
increased back to 6 g/L for the balance of the study.
FIG. 48 shows the CO conversion profile in the reactor with time. The CO conversion
was 80 percent or greater except during the upset at 1200 hr when the glucose
concentration in the feed was too high. Since cells were accumulating in the reactor with
time (as evidenced by the visual appearance of cells), it is noted that cell concentration
had little to no effect on CO conversion at a given retention time. This surprising result
was also seen in the CSTR studies (see Table 12) , where CO conversions of 90-100
percent were seen at all retention times studied. Similarly, the yield of H.sub.2 from CO,
shown in FIG. 49, was constant at 1.0 (theoretical) regardless of the experimental
conditions.
In comparing the immobilized cell reactor (ICR) with the CSTR with cell recycle (Table
13), it is seen that an 80 percent conversion of CO to H.sub.2 can be obtained at a 10 min
gas retention time in the CSTR with cell recycle. The H.sub.2 productivity in the CSTR
system was about 100 mmol/L-hr. In the immobilized cell reactor, an 80 percent CO
conversion was attained at a 5 min gas retention time based on void volume, or a 12 min
gas retention time based on total column volume. The productivity in the ICR was 270
mmole/L-hr based on void volume and 110 mmol/L.hr based on total column volume.
The immobilized cell rea ctor is thus a suitable substitute for the CSTR with cell recycle
and has the advantage of not requiring agitation.
Trickle bed reactors (TBR) are effective in promoting gas-liquid mass transfer and thus
are ideal for this application. Mass transfer is effected by flowing (or trickling) a small
stream of liquid over an inert packing while simultaneously flowing gas either
concurrently or countercurrently. For a biological system, the liquid contains cells in
addition to liquid medium. Also, the column is operated concurrently, which is a superior
operating mode for irreversible biological reactions.
FIGS. 50 and 51 present CO conversion and H.sub.2, productivity data for the trickle bed
reactor using ERIH2 at various gas retention times. All experiments were carried out at a
2 g/L glucose concentration, with 1 g/L yeast extract and I g/L trypticase in the medium.
As the retention time decreased, the productivity increased (FIG. 51), while the CO
conversion remained in the 80-100 percent range (FIG. 50). A summary of the trickle bed
reactor data is shown in Table 15. Both the gas flow rate (gas retentions time) and liquid
flow rate were changed during the study. As is shown in the table, the H.sub.2
productivity (based upon liquid volume in the reactor) was 69-216 mmole/L.hr. This
compares quite favorably with the CSTR productivities of 70-80 mmol/L.hr when the
volume of the packing in the trickle bed is considered.
Reaction rate has been shown to be proportional to pressure for many organisms
catalyzing gas-liquid reactions. More significantly, the size of the reactor in processing a
given quantity of gas is inversely proportional to pressure. It is thus economically
advantageous to operate at elevated pressures for these gas-liquid biological systems.
Experiments were carried out with ERIH2 in a batch high pressure Parr reaction vessel.
Glucose (0.9 g/L) in combination with trypticase (1 g/L) and yeast extract (1 g/L), was
added as the growth substrate. The key to success in these high pressure studies is to
maintain a high cell concentration in the reactor in order to keep the dissolved CO
tension (concentration) low. Since ERIH2 does not utilize CO for growth, an adequate
carbon source (glucose) concentration must be present to keep the cell density high,
especially when the pressure driving force is high.
FIGS. 52 and 53 show CO conversion, H.sub.2 production and optical density
measurements for ERIH2 in the high pressure Parr reactor. The bacterium was able to
utilize syngas at pressures as high as 100 psig. During the course of the experiment the
rate of conversion of CO increased, as denoted by the increase in slopes in FIG. 52 with
increased pressure. This indicates that operation at higher pressures is quite possible.
H.sub.2 production improved CO utilization as predicted by reaction stoichiometry. FIG.
53 shows that the pH dropped only slightly, perhaps because of the production of a by-
product (maybe acetic acid) as the glucose was consumed for cell growth. The optical
density rose from an initial level of 0.08 to 0.5
Non -aqueous fermentation studies were conducted to enhance the mass transfer rate of
the gaseous substrate, either by increasing the gas solubility or by reducing the mass
transfer resistance through reduced surface tension at the gas-liquid interface. There is no
information in the literature concerning the increase in CO solubility in the aqueous
phase or reducing the mass transfer resistance of CO. The selection of chemicals for the
study is based on the following criteria:
(1) Chemicals that can be dissolved into the aqueous phase.
(2) Chemicals with low toxicity, especially bio -products.
(3) Chemicals that can reduce the surface tension, which would increase the overall mass
transfer rate.
Potential chemicals are bio -polymers, bio -surfactants, and metabolism reactants or
products. Other possibilities are perfluorocarbons which have been reported to enhance
O.sub.2 transport into the aqueous phase. The study of the non -aqueous additives was
separated into two stages: initial screening and CSTR studies. The initial screening
studies were conducted in batch culture and only those materials showed good potential
were studied later in the CSTR.
The identification of the increase of the CO solubility/mass transfer rate in batch culture
is based on the CO consumption under mass transfer limited conditions. The gas phase
CO material balance in the batch reactor can be described as follows: ##EQUI## The
rate of disappearance of CO from the gas phase, dN.sup.G.sub.CO /dt, per unit of liquid
volume, V.sub.L, is proportional to the difference between the CO partial pressure in the
gas and liquid phases, P.sup.G.sub.CO-P.sup.L.sub.CO The proportionality constant is
the mass transfer coefficient, K.sub.L a, divided by Henry's Law constant, H, for CO.
During the course of a batch fermentation, the reaction is begun with a high gas
consumption. Eventually the reaction enters mass transfer limited conditions as
P.sup.L.sub.CO approaches zero. Under these conditions, the dissolved CO substrate
cannot satisfy the bacterial consumption rate. Simultaneous cell growth with gas
consumption is not needed to reach mass transfer limitations, although the time is
shortened with cell growth. Under mass transfer limitations, P.sup.L.sub.CO becomes
zero and a plot of dN.sup.G.sub.CO /dt verses P.sup.G.sub.CO is linear through the
origin, with a slope of K.sub.L a/H.
This concept was used to evaluate the effect of adding chemicals to enhance CO
solubility and gas transport. In the batch screening, the CO gas consumption is frequently
monitored, especially in the later stages of the fermentation, in both amended and control
runs. The gas consumption is computed and the value of K.sub.L a/H obtained as the
slope of the plot of gas consumption rate and composition. The effect of solvent and
chemical addition on CO utilization can be evaluated by comparing the values of K.sub.L
a/H. Since the Henry's law constant is defined as the solute partial pressure in the gas
phase per unit concentration of the solute in the liquid phase, the smaller the value of H,
the higher the gas solubility. Thus, larger values of K.sub.L a/H represent higher CO
solubilities when mass transfer coefficients are the same. Similarly, for chemicals that do
not affect solubility, higher K.sub.L a/H values show increased mass transfer rates.
In some cases, the mass transfer coefficient, K.sub.L a, may be affected by the additive.
The viscosity could be increased by the addition of a bio -polymer and K.sub.L a could be
reduced. The mass transfer coefficient could be increased by the addition of a surfactant
to reduce the surface tension. Under these conditions, the effect on CO solubility may be
difficult to assess. However, K.sub.L a/H is still the proper indicator for selecting
chemicals for non -aqueous fermentation.
Several chemicals were tested in batch culture. They include bio -polymers, bio -
surfactants, and organic compounds. In the bio -polymer group, xantham gum and dextran
were selected for study. The study of bio -surfactants concentrated on biological
detergents. The organic compounds included high carbon alcohols and perfluorocarbon
compounds. For each of these studies, four reactors of acclimated ERIH2 were used. The
mass transfer enhancing agent was added to two of the batch reactors. All the batch
reactors were regassed frequently with coal synthesis gas and gas compositions were
closely monitored. FIGS. 54 to 64 show the CO consumption in these batch studies and
FIGS. 65-75 show the plots of (-dCo/dt) (IN.sub.L) vs P.sup.G.sub.CO. The values of
K.sub.L a/H were calculated based on the above procedures. Table 17summarizes the
results of the various chemicals studied.
As is shown in Table 16, only some of the bio -surfactants, especially the non-ionic
biological detergents, show significant improvement in mass transfer rate. Most
impressive was the addition of 0.1 volume percent TYLOXAPOL .TM. detergent which
increased the CO mass transfer rate over 300 percent. Foaming during these studies
indicates that the effect of the addition of biological detergents was reduction of the
surface tension, rather than an increase in CO solubility. In general, bio -polymers
significantly improved the performance of the culture by reducing the mass transfer
resistance.
TYLOXAPOL .TM. detergent was chosen for study in the CSTR. In these experiments,
the gas retention time was controlled at 20 minutes. A dry cell density of at 0.4 g/L was
used with a 1/2 horsepower agitator. The CO conversion was measured at steady state as
the agitation was varied from 100 to 1000 rpm. At an agitation rate of 100 rpm, 0.01 or
0.015 volume percent TYLOXAPOL .TM. detergent was added to the culture and the gas
compositions were frequently monitored until equilibrium had been reached. The
agitation rate was then increased in 100 rpm increments until no further improvement
was observed.
FIG. 76 shows the effect of TYLOXAPOL .TM. detergent on CO conversion as a
function of agitation rate. TYLOXAPOL .TM. detergent had a minimal positive effect on
conversion at agitation rates up to 400 rpm. TYLOXAPOL .TM. detergent addition
decreased CO conversion at higher agitation rates. FIG. 77 shows the effect of EMCOL
CNP -I 10. TM. detergent on CO conversion by ERIH2. Again, the same trends as were
shown in FIGS. 76 were observed. It appears that surfactant addition in the low
concentrations needed to prevent toxicity are not sufficient to significantly promote mass
transfer.
K.sub.L a/H for the CSTR system can also be estimated from Equation (4), which
describes the CO material balance in a closed system. With the assumption of completely
mixed flow mass transfer limitation, P.sup.L.sub.CO becomes zero, and this equation can
be modified to describe the CSTR system: ##EQU2## In this equation, dN.sup.G.sub.CO
/dt is the steady state CO consumption, P.sup.0.sub.CO is the steady state outlet gas CO
partial pressure, and K.sub.L a/H will be a function of agitation rate. The steady state CO
consumption can further be related to the inlet CO partial pressure and conversion
through the ideal gas law by the following equation: ##EQU3## where P.sup.I.sub.CO is
the inlet CO partial pressure, V.sup.I.sub.G is the inlet gas flow rate, R is the ideal gas
constant, T is absolute temperature, and X is the CO conversion.
Since for every mole of CO consumed, two moles of gas are produced (1 mole H.sub.2
and 1 mole CO.sub.2) the determination of the outlet CO partial pressure is complicated
if the reaction is maintained at the same total pressure as the inlet gas. The flow rate of
the outlet gas stream, V.sup.O.sub.G will be larger than the inlet flow rate as shown by
the following equation: ##EQU4##
By the definition of conversion, P.sup.0.sub.CO can be estimated by the following
equations under constant temperature: ##EQU5## Equation (4) can then be rearranged
into: ##EQU6## By defining Y.sup.I.sub.CO=P.sup.I.sub.CO /P.sub.T, Equation (10)
can be rearranged as follows and K.sub.L a can be calculated with Co conversion, X, as
the major variable. ##EQU7##
This equation can be further simplified by utilizing the definition of gas retention time,
.theta.=V.sub.L N.sup.I.sub.G. ##EQU8## For a given synthesis gas composition,
Y.sup.l.sub.CO will be constant; for this gas mixture (CO:65%, H.sub.2 :20%, CH.sub.4
4%, CO.sub.2 : 11 %), the value is 0.64. if the operating temperature and gas retention
time are maintained constant, K.sub.L a/H will only be a function of conversion, which is
affected by the agitation rate. This equation is valid when the gas flow pattern inside the
reactor is completely mixed flow; and the reaction is under mass transfer limitation. The
gas flow pattern inside the reactor will change gradually from plug flow into completely
mixed flow as the agitation rate is increased from zero. Thus, this equation should be
appropriate under high cell concentrations and high agitation rates.
A summary of the mass transfer coefficients and CO consumption by ERIH2 in the
presence of various co -solvents and surfactants in batch culture is listed in Tables 17 and
18. As is noted in Table 17, several co-solvents/surfactants brought about an increase in
the mass transfer coefficient, K.sub.L a. The addition of 0.1 percent TRITON N-IOLTM.
detergent brought about an 84 percent increase in K.sub.L a compared to the control.
More significant were the additions of 0.1 percent NONIDET P-40.TM. detergent (107
percent increase), 0.1 percent Triton X-100 (203 percent increase) and 0.1 percent
TYLOXAPOL.TM. detergent (340 percent increase). A comparison of CO consumption
with and without some of the surfactants in Table 17 is presented in Table 18, Of the
surfactants listed, BRIJ 96.TM. detergent and TYLOXAPOL.TM. detergent brought
about increases in the Co consumption over the control. Longevity in increased CO
consumption was seen only with TYLOXAPOL.TM. detergent, which showed an
increase in CO consumption over the control even after two regassings. TYLOXAPOL
.TM. detergent is thus the surfactant of choice for the ERIH2 system based upon
increases in K.sub.L a and CO conversion, and the longevity of the CO increase.
The intrinsic kinetics for gas fermentations can be described by a modified Monod model
that includes substrate inhibition: ##EQU9## In the above equation, q is the specific
substrate uptake rate, P.sup.L.sub.CO is the liquid phase substrate concentration, q.sub.m
is the maximum achievable substrate uptake rate, K.sub.s is the monod saturation
constant, and W is the substrate inhibition parameter. This equation can further be
rearranged as: ##EQU10##
The difficulty in using the above equations for determining the intrinsic kinetic
parameters is the determination of the dissolved CO concentration, P.sup.L.sub.CO. The
measurement of small concentrations of CO in the liquid would be very inaccurate and
sensors are not available to determine the slightly soluble CO concentration. Therefore,
an indirect estimation method is used.
A CO material balance equation in batch fermentation defines the rate of disappearance
of CO from the gas phase, dN.sup.G.sub.CO N.sub.L dt, as proportional to the mass
transfer driving force, the difference between CO partial pressure in the gas phase
(P.sup.G.sub.CO) and liquid phase (P.sup.L.sub.CO), with the proportionality constant
the mass transfer coefficient, K.sub.L a/H: ##EQU1 I## The two unknowns in this
equation are the dissolved CO concentration, P.sup.L.sub.CO and the mass transfer
coefficient, K.sub.L a/H. Thus, if the value of the mass transfer coefficient is known, the
liquid phase CO concentration can be estimated from this equation. The mass transfer
coefficient can be obtained from the above equation when the batch fermentation is mass
transfer limited. In batch fermentations, the cell concentration increases as the gas is
consumed. However, the supply of the gas becomes limited as the cell concentration
continues to increase. P.sup.L.sub.CO becomes zero under mass transfer limitation, and
from Equation (15), the plot of the gas phase CO disappearance rate (IN.sub.L -
dN.sup.G.sub.CO /dt) vs P.sup.G.sub.CO is a linear relationship through the origin, with
a scope of K.sub.L a/H.
Once the volumetric mass transfer coefficient is known, the material balance equation
can be used to estimate the dissolved CO concentration in the region where
P.sup.L.sub.CO is not zero. These values can then be used to determine the values of
kinetic parameters by curve fitting the data to Equation (14).
The procedure to determine intrinsic kinetic parameters is to conduct a series of batch
fermentations with different CO partial pressure. From these data, mass transfer
coefficients for each run can be estimated by finding the slope of the linear range of
(IN.sub.L-dN.sup.G.sub.CO /dt) vs P.sup.G.sub.CO. Then the P.sup.L.sub.CO value
can be estimated by Equation (15). The intrinsic kinetic parameters, q.sub.m, K.sub.s,
and W can then be estimated by curve fitting of P.sup.L.sub.CO /q vs P.sup.L.sub.CO.
FIG. 78 shows gas phase partial pressure (P.sup.L.sub.CO) profiles for ERIH2 in batch
culture. Initial CO partial pressures ranging from 0.25-1.72 atm were used in the study.
As is noted, the times for complete CO utilization increased with increasing initial CO
partial pressure, ranging from 125 hr at 0.25 atm to 240 hr at 1.72 atm.
The determination of the mass transfer coefficient, K.sub.L a/H, for the batch bottle
experiments by Equation (15) is illustrated in FIG. 79. As is noted, a single straight line
is obtained for the mass transfer limited region of the fermentation, the P.sup.L.sub.CO
region from 0-0.3 atm. K.sub.L a/H has a value of
0.0025mmol/min.multidot.mL.multidot.atm, as determined from the slope of the straight
line. This compares well with previous batch experiments performed in these batch
bottles at the same agitation rate.
A plot of the liquid phase CO tensions, P.sup.L.sub.CO determined using Equation (15)
as a function of time is shown in FIG. 80. The liquid phase tensions range from 0 to l .75
atm. Finally, a plot of P.sup.L.sub.CO /q as a function of P.sup.L.sub.CO is shown in
FIG. 80. This plot is a rearrangement of Equation (13) as in Equation (14).
Thus, a plot of P.sup.L.sub.CO /q as a function of PLCo should yield a quadratic
equation of intercept Ks/q,sub.m, slope I/q.sub.m and curvature I/q.sub.m W.
From FIG. 81, the following equation for the specific uptake rate of ERIH2 as a function
of P.sup.L.sub.CO is obtained: ##EQU12## A similar expression was obtained for R.
rubrum: ##EQU 13## These equations may be used to compare the performance of these
two cultures.
A comparison of calculated specific CO uptake rates for the two bacteria is shown in
Table 19. As is shown, the specific uptake rate for ERIH2 is 1200-2000% higher than the
specific uptake rate of R. rubrum. This means that, for a given cell concentration, ERIH2
will utilize CO up to 20 times faster than R. rubrum, and without the need for light.
In a production scale operation the intermediate product will be primarily carbonic acid,
H.sub.2 CO.sub.3. Hydrogen removal from H.sub.2 CO.sub.3 is the product recovery
step for this example. There are a number of processes to remove CO.sub.2 from gas
streams. The separation is based on one of the following four principles (Eickmeyer et
al., 1978):
(1) CO.sub.2 is weakly acidic, forming H.sub.2 CO.sub.3 when dissolved in water. This
permits the use of liquid alkaline solutions, either regenerable or nonregenerable, for
absorption of CO.sub.2.
(2) CO.sub.2 is soluble in water and in many organic liquids. Processes based on
solubility as opposed to chemical affinity are also used.
(3) The molecular size and structure of CO.sub.2 permit it to be selectively adsorbed on
solid adsorbants, particularly molecular sieves.
(4) The acidic nature or size and structures of CO.sub.2 in some mixtures permit it to be
separated by the use of permeable membranes.
The amount of CO.sub.2 removed by solid adsorbents is small compared to that removed
by liquid absorbent systems. Permeable membrane separation is of minor commercial
importance (Eickmeyer et al., 1978). Hence, commercial processes are limited to either
alkaline solution absorption and physical solvents (solubility) absorption.
There are certain characteristic differences between processes based on physical
solubility and those based on chemical reaction with an alkaline solution. FIG. 82 shows
equilibrium lines for a typical chemical reaction system (20.5 wt % DEA) and for a
typical methanol solvent system (Eickmeyer et al., 1978). For the solvent system, the
CO.sub.2 content of the liquid phase increases in direct proportion to the partial pressure
of CO.sub.2 in the vapor phase. For the chemical reaction system, the equilibrium
pressure increases only slightly with loading of the liquid over the lower range of
solution loadings, but curves upward sharply as the loading approaches the
stoichiometric limit set by the chemical reaction. It is obvious that at high available
partial pressures of CO.sub.2 as in this application, the solvent system is capable of
attaining a higher loading of the scrubbing solution and, therefore, will require lower
solution circulation rates for the same degree of CO.sub.2 removal.
Another important advantage of the solvent system is at regeneration. The ratio of
stripping vapor/solution required to strip the solution to a very low residual CO.sub.2
content will be substantially less for the solvent system than for the chemical system.
Thus, a stripped solvent system will generally be capable of scrubbing the gas to be
treated to a lower level of residual CO.sub.2. Compared to a chemical system, the total
energy required for the solvent system per mole of CO.sub.2 removed is generally lower
and is composed of power for circulating the solution and, in many cases, for
refrigeration since the solubility of CO.sub.2 is greatly increased by operating at less than
ambient temperature.
Table 20 lists the typical operating conditions of various CO.sub.2 removal processes
(Eickmeyer et al., 1978). As discussed above, solvent systems involving sulfinol, selexol,
rectisol, purisol, and fluor appear to be most suitable. The feed gas in this application will
contain about 45% CO.sub.2 and a total pressure of 400 psi, or 180 psi CO.sub.2 partial
pressure. The majority of these solvents can also simultaneously remove H.sub.2 S, and
some solvents such as sulftnol and selexol even remove COS. The processes using these
solvents have the advantages of a low solvent circulation rate, low plant costs, low
utilities costs, high effectiveness for the removal of COS, CS.sub.2 and HS, low solvent
degradation and low corrosion rates (Eickmeyer et al., 1978). The use of these processes
entails payment of a royalty.
In light of the foregoing the following conclusions are offered
1. Rhodospirillum rubrum, strain ATCC 25903, has been identified as the best
photosynthetic bacterium to perform the water gas shift, showing a maximum specific
CO uptake rate of 16.0 mmol/g.multidot.hr.
2. A new bacterium, ERIH2, ATCC 55404 isolated from natural sources, rapidly
catalyzes the water gas shift reaction with stoichiometric H.sub.2 yields and without
requiring light for growth. The maximum specific CO uptake rate of ERIH2 is
200mmo1/g.hr. Small amounts of relatively inexpensive carbon sources such as glucose
may be utilized as growth substrates.
3. Monod -type kinetic expressions for specific substrate uptake rate by R. rubrum and
ERIH2 have been obtained.
4. Continuous culture operation with ERIH2 has been demonstrated in stirred tank and
trickle bed bioreactors. As an example, a CO conversion of 85 percent and H.sub.2 yield
of I00percent have been demonstrated in the CSTR with a gas retention time of 20
minutes and a 900 rpm agitation rate.
5. Chemicals have been added to the medium which have brought about a 340 percent
improvement in the rate of mass transfer of CO into the liquid phase in batch culture
while not negatively affecting the performance of the culture.
In accordance with another example of the present invention, municipal solid waste
(MSW) is converted to hydrogen by gasifying a municipal solid waste using air as the
oxident to produce a raw synthesis gas having a composition (percent by volume) of
about 16% CO, 8% CO.sub.2, 12% H.sub.2, and about 60% N.sub.2 cooling the raw
synthesis gas to about 30.degree. C., adding the cooled synthesis gas to a bioreactor with
an aqueous nutrient media and a microorganism ERIH2, converting at least the CO to
H.sub.2, venting the gases from the bioreactor, separating the hydrogen from the other
gases so as to recover hydrogen product.
In accordance with another example of the present invention, municipal solid waste is
converted to hydrogen by gasifying the municipal solid waste using an oxygen oxident to
produce a raw synthesis gas having percent by volume composition of about 49% CO,
about 15% CO.sub.2, and about 30% H.sub.2 cooling the raw synthesis gas to about
30.degree. C., adding the cooled synthesis gas to a bioreactor with an aqueous nutrient
media and the microorganism ERIH2, allowing the microorganism ERIH2 to convert at
least the carbon monoxide to H.sub.2, venting the gases from the bioreactor, and
separating the hydrogen from the other gases so as to recover a hydrogen product.
In accordance with another example of the present invention, sewage sludge is converted
to hydrogen by gasifying the sewage sludge to produce a raw synthesis gas having a
volume percent composition of about 37% CO, 27% CO.sub.2, and 35% H.sub.2, cooling
the synthesis gas to about 30.degree. C., adding the cooled synthesis gas to a bioreactor
with an aqueous nutrient media and the microorganism ERIH2, allowing the
microorganism to convert at least the carbon monoxide to hydrogen, venting the gases
from the bioreactor, separating the hydrogen from the other gases so as to recover a
hydrogen product.
In accordance with another example of the present invention, municipal solid waste
(MSW) is converted to hydrogen by gasifying a municipal solid waste using air as the
oxident to produce a raw synthesis gas having a composition (percent by volume) of
about 16% CO, 8% CO.sub.2, 12% H.sub.2, and about 60% N.sub.2, cooling the raw
synthesis gas to about 30.degree. C., adding the cooled synthesis gas to a bioreactor with
an aqueous nutrient media and a microorganism R. rubrum, converting at least the CO to
H.sub.2 venting the gases from the bioreactor, separating the hydrogen from the other
gases so as to recover hydrogen product.
In accordance with another example of the present invention, municipal solid waste is
converted to hydrogen by gasifying the municipal solid waste using an oxygen oxident to
produce a raw synthesis gas having percent by volume composition of about 49% CO,
about 15% CO.sub.2, and about 30% H.sub.2 cooling the raw synthesis gas to about
30.degree. C., adding the cooled synthesis gas to a bioreactor with an aqueous nutrient
media and the microorganism R. rubrum, allowing the microorganism R. rubrum to
convert at least the carbon monoxide to H.sub.2, venting the gases from the bioreactor,
and separating the hydrogen from the other gases so as to recover a hydrogen product.
In accordance with another example of the present invention, sewage sludge is converted
to hydrogen by gasifying the sewage sludge to produce a raw synthesis gas having a
volume percent composition of about 37% CO, 27% CO.sub.2, and 35% H.sub.2, cooling
the synthesis gas to about 30.degree. C., adding the cooled synthesis gas to a bioreactor
with an aqueous nutrient media and the microorganism R. rubrum, allowing the
microorganism to convert at least the carbon monoxide to hydrogen, venting the gases
from the bioreactor, separating the hydrogen from the other gases so as to recover a
hydrogen product.
In accordance with yet another example of the present invention, raw synthesis gas is
converted to hydrogen using the microorganism ERIH2 by cooling a synthesis gas to
about 50.degree. C. or less adding the cooled synthesis gas to a bioreactor along with an
aqueous nutrient media and the microorganism ERIH2, allowing the microorganism to
convert at least a substantial portion of the carbon monoxide to hydrogen, and recovering
the hydrogen from the bioreactor.
In accordance with yet another example of the present invention, raw synthesis gas is
converted to hydrogen by a microorganism R. rubrum by cooling the synthesis gas to
about 50.degree. C. or less, adding the cooled synthesis gas to a bioreactor along with an
aqueous nutrient media and the microorganism R. rubrum, allowing the microorganism
to convert most of the carbon monoxide to hydrogen, and recovering the hydrogen from
the bioreactor.
In accordance with still yet another example of the present invention, synthesis gas
having a volume percent composition of about 10 to 50% CO, 5 to 40% CO.sub.2 and 10
to 35% H.sub.2 is supplied to a bioreactor as a gaseous substrate along with an aqueous
nutrient media and an anaerobic bacteria capable of converting carbon monoxide to
hydrogen, allowing the microorganism to convert most of the carbon monoxide to
hydrogen, and recovering the hydrogen from the bioreactor.
In accordance with another embodiment of another example of the present invention,
waste biomass is converted to hydrogen by gasifying the waste biomass to produce a
synthesis gas having at least 10 to 50% by volume carbon monoxide, converting the
carbon monoxide in the synthesis gas to hydrogen by a microorganism selected from at
least one of ERIH2 or R. rubrum and a bioreactor along with an aqueous nutrient media,
and recovering the hydrogen produced.
In accordance with another example of the present invention, hydrogen is separated from
the other gases vented from a bioreactor by a sulfinol process.
In accordance with yet another example of the present invention, at least one of the
microorganisms ERIH2 and/or R. rubrum is used to convert the carbon monoxide from a
synthesis gas produced by gasification of waste biomass into hydrogen.
In accordance with yet still another example of the present invention, biomass waste
selected from at least one of municipal solid waste, sewage sludge, plastic, tires, coal,
and mixtures thereof is converted into a useful product hydrogen by gasifying the
biomass waste to produce a synthesis gas containing carbon monoxide, converting the
carbon monoxide to hydrogen using a microorganism selected from one of R. rubrum and
ERIH2.
Thus, it will be appreciated that, as a result of the present invention, a highly effective,
improved biological process for converting waste biomass to useful products, process for
converting synthesis gas to hydrogen, and microorganism is provided by which the
principal objective, among others, is completely fulfilled. It is contemplated, and will be
apparent to those skilled in the art from the preceding description and accompanying
drawings, that modifications and/or changes may be made in the illustrated embodiments
without departure from the present invention. Accordingly, it is expressly intended that
the foregoing description and accompanying drawings are illustrative of preferred
embodiments only, not limiting, and that the true spirit and scope of the present invention
be determined by reference to the appended claims.
REFERENCES
Anderson, L. and R. C. Fuller. "Photosynthesis in Rhodospirillum rubrum I. Autotrophic
Carbon Dioxide Fixation," Plant Physiol 42, p. 487 (1967).
Balch, N. E. and R. S. Wolfe. Appl. Environ. Microbio]., 32, 781-791 (1976).
Barik, S., R. E. Corder, E. C. Clausen, and J. L. Gaddy. Energy Progress, 7, p. 157
(1987).
Bhatnagar, L., J. A. Krzycki, and J. G. Zeikas. "Analysis of Hydrogen Metabolism in
Methanosarcina barkeri: Regulation of Hydrogenase and Role of C -dehydrogenase in
H.sub.2 Production," FEMS Microbiology Letter, 41, pp. 337-343 (1987).
Bott, M., and R. K. Thauer. "Proton Translocation Coupled to the Oxidation of Carbon
Monoxide to CO.sub.2 and H.sub.2 in Methanosarcina barkeri," Eur. J. Biochem. 179,
pp. 469-472 (1989).
Bryant, M. P. "Commentary on the Hungate Technique for Culture of Anaerobic
Bacteria," Amer. J. Clin. Nutr. 25, pp. 1324-1328(1972).
Daniels, L. G., G. Fulton, R. W. Spencer, W. H. Orme-Johnson. "Origin of Hydrogen in
Methane Produced by M. thermoautotrophicum, J. Bacteriol. 14, pp. 694-698 (1980).
Dashekvicz, M. P. and R. L. Uffen. "Identification of a Carbon Monoxide -Metabolizing
Bacterium as a Strain of Rhodopseudomonas gelatinosa (Molisch) van Niel," Int'l J. of
Syst. Bacteriol, 29, pp. 145-148 (1978).
Diekert, G. and M. Ritter. "Carbon Monoxide Fixation into the Carboxyl Group of
Acetate During Growth of Acetobacterium woodiion H.sub.2 and CO.sub.2," FEMS
Microbiol. Letters, 17, pp. 299-302 (1983).
Eickmeyer, A. G., R. R. Johnson, and B. G. Goar. "Carbon Dioxide Removal",
Encyclopedia of Chemical Processing and Design. J. J. McKeHa Ed., V.6. 1978. pp.292-
310.
Fuller, R. C. "Photosynthetic Carbon Metabolism in the Green and Purple Bacteria, "The
Photosynthetic Bacteria, ed. by R. K. Clayton and W. R. Sistrom, Plenum Press, New
York, pp. 691-705(1978).
Gest, H., M. D. Kamen and H. M. Bregoff J. Biolog. Chem., 182, p. 153 (1950).
Goar, G., "Sulfinol process has several key advantages", Oil & Gas J. Jun. 30, 1969. pp.
117-120.
Hansen, T. A. "Electron Donor Metabolism in Phototrophic Bacteria," in J. G. Ormerod
(ed.) The Phototrophic Bacteria: Anaerobic Life in the Light, University of California
Press, Berkeley and Los Angeles pp. 76-99 (1983).
Hegemann, G. "Oxidation of Carbon Monoxide by Bacteria," Trends in Biochemical
Sciences, 5, pp. 256-259 (1980).
Hessley, R. K., J. W. Reasoner, and J. T. Riley. Coal Science, Wiley, N.Y. (1986)
Hirsch, P. "Photosynthetic Bacterium Growing Under Carbon Monoxide," Nature, 217,
pp. 555-556 (1968).
Hungate, R. E. "A Roll Tube Method of Cultivation of Strict Anaerobes," in Methods in
Microbiology, Vol. 5b, Academic Press, New York (1969).
Keppen, O. I., A. N. Nozhevnikova, and V. M. Gorlenko. Microbiology, 45, pp. 10-13
(1976).
Ko, C. W., J. L. Vega, S. Barik, E. C. Clausen, and J. L. Gaddy. "Biological Production
of Methane from Coal Synthesis Gas Under High Pressure," presented at the AIChE
Summer National Meeting, Minneapolis, Minn. (1987).
Lorowitz, W. H. and M. P. Bryant. "Peptostreptococcus productus Strain that Grows
Rapidly with Carbon Monoxide as the Energy Source," Appl. Environ. Microbiol., 47, p.
961-964 (1984).
Martin, D. R., L. L. Lundie, R. Kellum, and H. L. Drake. "Carbon Monoxide -Dependent
Evolution of Hydrogen by the Homoacetate-Fermenting Bacterium Clostridium
thermoaceticum," Curr. Microbiol, 8, pp. 337-340 (1983).
Meyer, O. and H. G. Schlegal. "Biology of Aerobic Carbon Monoxide -Oxidizing
Bacteria," Annual Reviews of Microbiology, 37, pp. 277-310 (1983).
O'Brien, J. M., R. H. Wolkin, T. T. Moench, J. B. Morgan, and J. G. Zeikus. "Association
of Hydrogen Metabolism with Unitrophic or Mixotrophic Growth of Methanosarcina
barkeri on Carbon Monoxide," J. Bacterioi. 158, pp. 373-375 (1984).
Payne, K. R. Chemicals from Coal, Wiley, N.Y. (1987).
Quayle, J. R. and N. Pfenning. "Utilization of Methanol by Rhodospirillaceae," Arch.
Microbio]., 102, pp. 193-198 (1975).
Spratt, H. G. and J. S. Hubbard. "Carbon Monoxide Metabolism in Roadside Soils,"
Appl. and Environ. Microbiol., 41, pp. 1192-1201(1981).
Stupperich, E., K. E. Hammel, G. Fuchs, and R. K. Thauer. "Carbon Monoxide Fixation
into the Carboxyl Group of Acetyl Coenzyme A During Autotrophic Growth of
Methanobacterium," FEBS Lett., 152, pp. 21-23 (1983).
Tracy, C. A., and E. Ashare. "Biomethanation of Biomass Pyrolysis Gases," Dynatech
R/D Company Final Report on SERI Contract No. XB -9-8356-1, Cambridge, Minn.
(1981).
Uffen, R. L. "Anaerobic Growth of a Rhodopseudomonas Species in the Dark with
Carbon Monoxide as Sole Carbon and Energy Substrate," Proc. Nat'l. Acad. Sci., 73, pp.
3298-3302(1976),
Uffen, R. L. "Metabolism of Carbon Monoxide," Enzyme and Microbiol. Technol., 3, pp.
197-206 (1981).
Uffen, R. L., C. Sybesma, and R. S. Wolfe. "Mutants of Rhodospirillum rubrum Obtained
After Long -Term Anaerobic Dark Growth," J. Bacterio. 108, pp. 1348-1356 (1971).
Vega, J. L., G. M. Antorrena, E. C. Clausen, and J. L. Gaddy. "Biological Production of
Liquid and Gaseous Fuels from Coal Synthesis Gas," ACS Symposium Series, (I 988a).
Vega, J. L., G. M. Antorrena, E. C. Clausen, and J. L. Gaddy. "Study of Gaseous
Substrate Fermentations: Carbon Monoxide Conversion to Acetate, 2. Continuous
Cultures," Biotechnol. and Bioeng., (1989b).
Vega, J. L., V. L. Holmberg, E. C. Clausen, and J. L. Gaddy. "Fermentation Parameters
of Peptostreptococcus productus on Gaseous Substrates (CO, H.sub.2 /CO.sub.2),"
Archives in Microbiology, (1988b).
Vega, J. L., K. T. Klasson, D. E. Kimmel, C. W. Ko., E. C. Clausen, J. L. Gaddy, "Sulfur
Toxicity," Topical Report DOE Contract DE-AC-21-86MC23281, METC (1989).
Wender, I. "Catalysts in Conversion of Synthesis Gas," in Chemicals from Coal, K. R.
Payne (ed.) Wiley, N.Y. (1987).
TABLE 1
Municipal Solid Waste (MSW) Gasification - Syngas Composition
(% by vol)
Gasifica-
Vigel Black
Groeneveld
Groeneveld
Groeneveld
tion et al eta]
Purox Bailie Purox
Medium air air
oxygen oxygen and
oxygen
(Plant)
(pilot) (pilot)
(commercial)
steam (pilot)
(pilot)
49.0 20.0 40.0
CO 16.5 11.6
CO.sub.2
8.5 15.4
15.0 39.0 24.0
H.sub.2
12.5 12.5
30.0
30.0 24.0
O.sub.2
27.0
25.30 25.31 27.63
2.4 0.8
35.0
N.sub.2, Ar
N.sub.2 + Ar
0.6
60.1 45.1
1.0
1.0
CH.sub.4 2.5
3.0
5.0 5.6
C.sub.2.sup.+ 3.2
2.0
6.0
H.sub.2 S, COS
5.4
for CO, CO.sub.2, H.sub.2
only basis
CO 44.0 29.4
52.1
22.5 45.4
CO.sub.2
22.7 39.0
16.0
43.8 27.3
H.sub.2
33.3 31.6
31.9
33.7 27.3
TABLE 2
Syngas Produced by the Gasification of Sewage Sludge
Vol %
Texaco Texaco
Texaco Carver- Carver-
Com- Davis et al.,
Zimpro A, Greenfield B,
Greenfield C,
ponent1990 1989 1989 1989
CO 37.0
37.09 36.40 34.96
CO.sub.2
27.0
25.30 25.31 27.63
H.sub.2
35.0
35.26 35.74 35.49
N.sub.2 + Ar
0.6
1.68 1.84 1.10
H.sub.2 S, CS.sub.2,
0.3
0.65 0.71 0.80
COS
CH.sub.4
0.1
0.02 0 0.02
TABLE 3
Characteristics of Generic Types of Gasification Reactors
MOVING -BED FLUIDIZED -BED ENTRAINED -FLOW
Ash Conditions
Dry Ash Slagging Dry Ash Agglomerating
Slagging
Feed Characteristics
Coarse Coarse Crushed Crushed Pulverized
Size (0-2 inch)
(0-2 inch)
(0-114 inch)
(0-114 inch)
(0-100 mesh)
Acceptability of Fines
Limited Better than dry ash
Good Better Unlimited
Acceptability of
Yes (with/
Yes (with/
Possibly Yes Yes
Caking Coal
modifications)
modifications)
Preferred Coal Rank
Low High Low Any Any
Operating
Characteristics
Exit Gas Temperature
Low Low Moderate Moderate High
(800.degree. F.-1200.degree. F.)
(800,degree. F.-1200.degree. F.)
(I700.degree. F.-1900.degree. F.)
(I700.degree. F.-1900.degree.
(>2300.degree. F.)
Oxidant Requirement
Low Low Moderate Moderate High
Steam Requirement
High Low Moderate Moderate Low
Key Distinguishing
Hydrocarbon liquids/
Large char recycle
Large amount/
Characteristics
in the raw gas
TABLE 4
of sensible
heat energy/
in the hot/
raw gas
Summary of Performance of R. rubrum strains
Strain
25903 9791 11170 19613
Inoc-
CO CO CO CO
ulum Concert. H.sub.2
Concen.
H.sub.2
Concen.
H.sub.2
Concen.
H.sub.2
level
mmol/g Yield mmol/g
Yield
mmol/g
Yield
mmol/g
Yield
g/L hr % hr % hr % hr %
0.50 17.3
84
16.6
74
17.3
84
16.8
79
0.57 14.7
79
16.0
85
14.1
89
12.7
87
0.54 13.3
78
13.5
77
13.9
74
12.5
72
0.40 14.3
83
16.8
72
13.9
76
18.5
67
0.45 18.0
82
17.8
78
15.8
82
18.6
79
Aver -
15.5
81
16.1 77
15.0 81
15.8 77
age
TABLE 5
Growth of ERIH2 on Different Sugars, 2 g/L.
Day 0 Day 1 Day 2
Sugar Cells (g/L)
Cells (g/L)
pH Cells (g/L)
Arabinose 0.054
0.230
7.15 0.188
Fructose 0.051
0.353
6.78 0.250
Galactose 0.061
0.447
6.89 0.578
Glucose 0.046
0.438
6.83 0.257
Mannose 0.053
0.490
6.74 0.294
Ribose 0.051
0.176
6.60 0.362
Rhamnose 0.053
0.421
7.02 0.147
Xylose 0.050
0.513
6.65 0.249
TABLE 6
Evaluation of Corn Steep Liquor as a Growth Co -Substrate for
ERIH2
Cell Concentration (g/L)
0 3 hr 5.5 hr 22 hr 27 hr
Glucose
(2 g/L) 0.042 0.070 0.216 0.283 0.254
Glucose
(2 g/L) + Com steep Liquor
(2 g/L)
0.064 0.1400.319
0.301 0.282
Glucose
(4 g/L) 0.038 0.071 0.195 0.458 0.391
Glucose
(4 g/L) + Com steep liquor
(2 g/L)
0.064 0.1400.302
0.499 0.466
TABLE 7
The Growth of ERIH2 on 5 g/L Glucose and Galactose.
Day 0 Day 1 Day 2
Sugar Cells (g/L)
Cells (g/L)
pH Cells (g/L)
pH
Galactose
0.062 0.185 7.21 0.774 5.87
Glucose 0.054 0.779 5.50 0.872 5.06
TABLE 8
Growth and Metabolism of Glucose by ERIH2
(0.75 g/L Glucose)
Time
(hr) pH Cells (g/L)
Ammonia (mg/L)
Glucose (g/L)
0
6.9
0.061
131
0.73
4
7.0
0.163
139
0.58
8
7.2
0.298
154
0.45
11.5
6.9
0.430
161
0.04
24
6.6
0.343
170
0.04
TABLE 9
Growth and Metabolism of Glucose by ERIH2
(1.5 g/L Glucose)
pH Cells (g/L)
Ammonia (mg/L)
Glucose (g/L)
Time Bot. Bot, Bot. Bot. Bot. Bot. Bot. Bot.
(hr) 1 2 1 2 1 2 1 2
0 6.94 6.73 0.073
0.073
124 128 1.54 1.63
4 7.30 7.01 0.142
0.241
141 163 1.40 1.34
8 7.11 6.57 0.258
0.718
162 147 1.24 0.17
20 6.58 6.35 0.579
0.479
171
TABLE 10
170 0.10 0.11
Maximizing the Growth of ERIH2 in Various
Supplemented Nutrient Media.
Medium supplement (g/L)
Glucose Yeast Extract Tripticase
Cells (g/L)
10
15
2
1.39
10
15
5
1.50
10
15
10
1.39
10
15
15
1.43
10
15
20
1.40
5
5
2
0.91
5
10
2
0.97
5
15
2
1.02
5
20
2
1.10
25
10
5
3.50
25
20
5
4.92
25
20
5
4.96
(with pH adjustment)
TABLE 11
The Comparison of CO Conversion in the CSTR
Gas Retention
CO Conversion (percent)
Time R. rubrum Isolate I
Isolate 2
10 min
20.0
52.5
75.0
20 min
38.0
81.3
87.0
30 min
52.0
87,8
91.2
45 min
65.0
91,7
93.5
60 min
73.8
93.0
94.7
90 min
81.2
94.1
96.8
Average H.sub.2 Yield
70.0
95.0 95.0
TABLE 12
CO Conversion (percent) in the CSTR with ERIH2
Agitation
Gas Retention Time
(rpm) 30 minutes 15 minutes
10 minutes
200 3.50 3.5 3.65
300 10.48 8.01 13.56
400 44.37 27.52 26.67
500 56.0 54.01 38.68
600 65.15 62.26 49.21
700 74.65 66.31 58.65
800 78.43 70.92 61.58
900 80.96 73.75 65.6
1000 82.85 75.80 68.88
TABLE 13
Steady State Performance of ER12 in the CSTR with Cell
Recycle
(10 g/L glucose)
Retention H.sub.2 H.sub.2
Time CO Conversion
Yield Cell Conc.
Productivity
(min) (%) (%) g/L (mmole/l hr)
21.6 85.3 100.0 3.312 59.7
18.4 85.0 100.0 3.064 69.2
16.0 83.6 90.9 3.088 71.1
12.8 81.4 86.9 3.128 82.6
8.1 78.5 93.3 3.0 134.0
Dilution rate:
0.026 hr.sup.-1
TABLE 14
Effects of Dilution Rate and Gas Retention Time
on the Performance of ERIH2 in the CSTR (2 g/L glucose)
Liquid
Dilution Retention
CO
Rate Time Conversion H.sub.2 Yield
Cell
(hr.sup.-1)
(min) (%) M g/L
0.007
18.9
73.6
100
0.603
0.014
21.2
80.4
94.5
0.686
0.021
19.6
83.4
93.7
0.84
TABLE 15
Performance of ERIH2 in the Cocurrent Trickle Bed
Reactor
Gas
Gas Flow
Liquid Flow
Retention CO H.sub.2
Rate Rate Time* Conversion
Productivity
(ml/min)
(ml/min) (min) (%) (mmole/L .multidot. hr)
12.50
0.28
24.00
99.40
69.0
19.50
0.28
15.38
90.08
97.2
22.10
0.28
13.57
89.21
109.2
25.10
0.28
11.95
92.13
127.8
28.90
0.28
10.38
90.42
144.6
34.50
0.37
8.70
85.16
162.6
39.63
0.37
7.57
87.80
192.6
42.50
0.37
7.06
86.07
202.2
45.60
0.37
6.57
85.47
216.0
*based upon fluid volume in reactor
TABLE 16
Calculated Mass transfer Coefficients for ERIH2
in the Presence of Co-Solvents/Surfactants
K.sub.L a
(mmol/ml/min/
Co -Solvents/
Concentration atm .times. 1000)
Surfactant
(v/v %) Control Sample % Change
Glycerol 10.0 2.05 1.66 -16
Dextran 0.1
2.64 2.33 -15
Xantham Gum
0.025
1.70 1.67 -2
FC -40 10.0
3.02 2.84 -6
Tween 85 0.1
1.91 1.46 -25
Tergital0.1
2.08 1.99 -4
Tyloxapol
0.1
3.41 15.00 +340
Nonidet P-40
0.1
2.54 5.25 +107
Triton N-42
0.1
2.95 1.65 -44
Triton N-101
0.1
3.12 5.75 +84
Triton X-15
0.1
2.40 2.27 -5
Triton X-100
0.1
2.35 7.12 +203
Span 85 0.1
2.12 1.95 -8
Tyloxapol
0.1
+ Corn Oil
0.2
2.77 2.61 -6
TABLE 17
Summary of Non -Aqueous Solvent Screening
K.sub.L a/H
Addition
(10.sup.3 mmol/ml/miwatm)
Increase
Compounds (Volume %)
Control Amendment
(percent)
A. Bio -polymers
Dextran 0.1 2.64 2.33 -15
Xanthan gum
0.025 1.70 1.67 -2
B. Bio -surfactants
Triton N-42
0.1 2.95
Tween 85 0.1
Triton X-15
1.65 -44
1.91 1.46 -25
0.1 2.40 2.27 -5
Tergital 0.1 2.08 1.99 -4
Triton N-101
0.1 3.12
Nonidet P-40
0.1 2.54
Tyloxapol 0.1
C. Organic
Compounds
5.75 +84
5.25 +107
3.41 15.00 +340
Glycerol 10.0 2.05 1.66 -16
FC -40 10.0 3.02 2.84 -6
(perfluoro)
TABLE 18
Comparison of CO Consumption by ERIH2
In the Presence of Surfactants
CO Consumption (%)
Control
Sample
Tyloxapol (0.1 %, v/v)
First Gassing
100 113.24
Regassing
100 129.14
Second Regassing 100 124.18
Brij 96 (0.025%,
w/v)
First Gassing
100 101.70
Regassing
100 24.65
(0.05%, w/v)
First Gassing
100 110.08
Regassing
100 33.62
(0.0107%, w/v)
First Gassing
100 109.61
Regassing
100 24.91
Nonyl Alcohol (0.1%,
v/v)
100
98.93
Oleyl Alcohol (0.1%, v/v)
100
95.02
Propylene Glycol (0.1
%, v/v)
100
98.33
Cyclohexane (0.1%, v/v)
100
97.76
TABLE 19
Comparison of Calculated Specific CO Uptake Rates of
R. rubrum and ERIH2
q, mmol/hr .multidot. gcells
P.sup.L.sub.CO, atm
R. rubrum
ERIH2
0.1
8.73
181.39
0.2
10.92
191.56
0.4
9.58
139.13
0.6
7.69
102.86
0.8
6.28
80.65
TABLE 20
Typical Operating Conditions of Various CO.sub.2 Removal Processes
CO.sub.2 in Feed
Operating Conditions
Net Gas Pressure
Solution Loading
CO.sub.2 by
(lb./in.sup.2
Temperature
Utilities
Process
Composition
(scf/gal)
Volume
gauge)
(.degree.F.)
Heat
� X11
Catacarb
Varies
3-5.5
2-27
100-1200
100-260
Low Medium
Benfield
K.sub.2 CO.sub.3 +
3-5.5
2-27
100-2000
100-260
Low Medium
promotor
Vetrocoke
Varies
Not 2-27
100-1200
120-212
Low Medium
known
Conventional
15-20%
2.5-3.5
0.5-10.0
25-950
80-130
High
High
MEA
High -loaded
30-40%
7 15-25
400-900
130-160
Medium
Medium
MEA
Conventional
20-25%
2-3 0.5-0.8
175-500
80-130
High
High
DEA
High -loaded
25-27%
5-5.4
2.0-20
175-950
80-130
Medium
Medium
DEA
SNPA:DEA
25-30%
5.5-6.2
2.0-30
200-2000
80-130
Medium
Medium
DGA 65-70%
5-7 5.0-20
150-950
80-130
Medium
Medium
Sulfinol
Varies
8-162.0-30
300-1000
100-160
Medium
Low
Selexol
DMPEG 11-15
2.0-45
500-1400
100-160
Low Low -medium
Rectisol
Methanol
5-202.0-35
300-1200
-5 to -100
Low Medium
Purisol
NMP 5-10 5.0-35
450-1200
40-105
Low Medium
Fluor Propylene 5.0-53
carbonate
*/Depends on solubility and recompression of flash gas
Note:
NMP: nmethyl 2pyrrolidone
DMPEG: dimethyl ether of polyethylene glycol
Sulfinol solvent: sulfolane, diisopropanol amine
TABLE 21
Modified Medium for R. rubrum
(without YE, NH3 and Trypticase)
1. Salt C 80.0 ml
2. PFN trace 1.0 ml
3. Vitamin 5.0 ml
4. Cysteine HCL 0.5 g
5. CaCl.sub.2 2H.sub.2 O 0.06 g
6. NaHCO.sub.3 2.0 g
7. Distilled water 920.0 ml
8. Adjust pH to 7.0 under 20% CO.sub.2 and 80% N.sub.2.
9. Bubbled under 20% CO.sub.2 and 80% N.sub.2 for 30 min.
10. Tubed anaerobically and autoclaved for 15 min.
11. Trypticase, glucose or NH.sub.3 is added as required.
TABLE 22
Medium for ERIH2
1. Salt C 80.0 ml
2. Yeast extract 1.0 g
3. Trypticase 1.0 g
4. PFN trace 3.0 ml
5. Vitamin 10.0 ml
6. Glucose 2.0 g
7. CaCl.sub.2 2H.sub.2 O 0.06 g
8. NaHCO3 2.0 g
9. Resazurin (0.01 %) 1.0 ml
10. Distilled water 920.0 ml
11. Adjust pH to 6.6 under 20% CO.sub.2 and 80% N.sub.2.
12. Bubbled under 20% CO.sub.2 and 80% N.sub.2 for 20 min.
13. Tubed anaerobically and autoclaved for 15 min.
TABLE 23
Medium for R. rubrum (ATCC)
1. PFN salt 50.0 ml
2. PFN trace 1.0 ml
3. B -vitamin 5.0 ml
4. NH.sub.4 Cl 2.7 g
5. Yeast Extract 1.0 g
6. Distilled water 944.0 ml
7. Boiled under 80% N.sub.2 and 20% CO.sub.2.
8. Cooled and add 4.0 g NaHCO.sub.3.
9. Tubed under 80% N.sub.2 and 20% CO.sub.2,
10. Autoclaved for 15 min.
3
Virginia Isbell
Chair, Finance Committee
Hawaii County Council
75-5706 Hanama Place, Suite 109
Kailua-Kona, HI 96740-1713
Re: BRI Process Technology
Dear Ms. Isbell:
Street, Suite F • New Smyrna Beach, FL 32168
ne: 386.423.0120 • Fax: 386.478.0084
July 28, 2005
Please be advised that Pacific Waste, Inc., a Hawaii corporation with its principal offices in Kailua-
Kona, Hawaii, as ourjoint venture partner, has the exclusive right to utilize the proprietary
gasification/biocatalytic technology ("Technology") of Bioengineering Resources Inc. within the State
of Hawaii.
The Technology will co -produce fuel grade ethanol and low-cost "green" electric power from organic
wastes and/or hydrocarbons, and it also may be used to produce other products or by-products, such as
hydrogen or protein for animal feed.
Please accept this letter as our authorization to allow Pacific Waste, Inc. and its agents and employees to
represent our interests throughout the State of Hawaii and to explain not only our Technology, but our
proposal for a renewable energy plant.
Please do not hesitate to contact me if you need further documentation or authorization.
Sincerely,
William F. Bruce, President
BRI Energy, Inc.
4
The Co -Production
of Ethanol and Electricity
From Carbon -based Wastes
A Report on a New Technology
that addresses multiple Energy
and Waste Disposal solutions
BioEnergy Hawaii
a joint venture of
Pacific Waste, Inc.
808.326.4911
BioConverter LLC
310.822.1960
BRI Energy LLC
323.650.5095
www.brienergy.com
July 2005
BRI ENERGY, LLC
THE CO -PRODUCTION OF ETHANOL & ELECTRICITY
FROM CARBON -BASED WASTES
Carbon -based wastes represent one of the world's most promising and virtually
untapped renewable energy sources. In the United States, more than 1.5 billion tons
of municipal solid waste, biosolids, agricultural, forestry and other waste products are
generated each year.
There is a growing awareness that new and environmentally sensitive means of waste
disposal must be developed. For example, methane generated from the
decomposition of landfilled wastes contributes to global warming, and when wastes
are burned, they create potentially toxic pollutants in particles and gases.
During the past 25 years, government and private industry in the United States have
spent some $9 billion attempting to develop economic and environmentally sound
methods for the production of electricity and liquid energy from organic materials, and
thus, free society from its dependence on fossil fuels
The State of Hawaii, which currently generates an estimated three million tons of
municipal solid waste per year, is an example of a region in critical need of domestic
energy sources.
Isolated geographically, Hawaii relies on imported petroleum for 90% of its energy. It
has no conventional energy resources such as oil, coal or natural gas.
Hawaii uses 24.6% of its imported oil to generate 85% of its electricity (the nation as a
whole uses only 3.2% of its petroleum resources to generate electricity).
The state's on -road gasoline usage will increase from 455 million gallons in 2004 to
550 million gallons by 2015. Meanwhile, jet fuel accounts for 32% of the state's total
energy consumption.
The State has now mandated the 10% blending of ethanol, although it has no
domestic ethanol production. If no domestic production is developed, 10% blending of
ethanol will require the importation of at least 50 million gallons of ethanol.
Therefore, to encourage the domestic production of ethanol, Hawaii has instituted a
30 -cent per gallon ethanol facility tax credit, which is in addition to the 51 -cent per
gallon federal subsidy.
Ethanol has a major role to play in the mix of alternate energy sources. It ads as a
volume extender when blended with gasoline, it improves octane performance and
operates as an oxygenate, reducing automobile emissions and CO2 when produced
from biomass. The blending of ethanol with gasoline is already an established
practice in the United States. It is being used around the world in gasoline blends of
10-85%. Today's automobiles can operate efficiently on blends of 20% or higher.
(Brazil has set of goal of operating its vehicles on 100% ethanol by 2007.)
However, ethanol, to date, has been produced chemically from ethylene or biologically
from the fermentation of sugars from carbohydrates found in agricultural crops like
com kernels. Sugar fermentation has been the only process to commercially produce
ethanol from biomass. However, it is inefficient and uneconomic. Not a single gallon
would be produced in the United States today without state and federal subsidies (a
51 -cent per gallon federal tax credit, plus additional incentives ranging from five to 28 -
cents per gallon in the com-producing states).
Further, the fact that, to date, it has only been produced from com kernels (and sugar
cane in Brazil) has limited its potential as a substitute for gasoline. For example, only
about 6-8 billion gallons could be produced from available cropland in the United
States (only 4% of the nation's current demand for fuel), without impacting the price
and availability of com in other products and markets.
If electricity and ethanol could be produced profitably from biomass, it could expand
the nation's supply of electrical energy, supplement gasoline, convert vast quantities of
organic waste into energy and contribute meaningfully to the nation's goal of energy
independence.
This BRI Renewable Energy Process makes these goals achievable.
The BRI Renewable Energy Process
A new gasification/fermentation process developed for BRI Energy, Inc. ("BRI") by a
team led by Dr. James L. Gaddy of Fayetteville, Arkansas, makes possible the co-
production of electricity and ethanol from any carbon -based materials, including:
• Municipal Solid Waste
• Biosolids & Animal Wastes
• Green Waste
• Agricultural residues
• Used Tires & Plastics
• Timber and Wood Wastes
• Coal, natural gas and other hydrocarbons
• Refinery Tars & Waste Oils
Efficient and economically viable, the BRI process utilizes an enzyme from patented
bacteria, which ingests synthesis gas (gasified wastes) and emits pure ethanol at a
yield of 75 gallons or more per dry ton of biomass. From used tires or hydrocarbons it
can yield 150 gallons or more per ton.
Unlike combustion processes, thermal gasification decomposes organic materials into
their basic molecular structure at temperatures of up to 2,200°F in a reducing, oxygen -
starved atmosphere.
Before being introduced to the bacteria in a fermentation tank, the synthesis gases
(CO, H2 and CO2) must be cooled to approximately 98017—a process that generates an
enormous amount of waste heat that can be used to create high temperature steam to
drive electric turbines.
In the fermentation step, the patented bacteria ingest the syngas and emit ethanol and
water, which is then distilled away to produce pure industrial or fuel -grade ethanol.
Contrary to current sugar fermentation technologies, the process is odorless.
The bacterial culture is anaerobic and dies when exposed to air. It has a
Biosafety Level 1 health hazard rating (the lowest possible for microorganisms).
The process creates no environmental or health hazards, ground or water
contamination, and minimal air emissions. Its residue is a non -hazardous ash.
When biomass is used to co -produce ethanol and electricity, significant
reductions in greenhouse gas emissions can be achieved.
The BRI process will gasify any carbon -based material whose moisture content is less
than 40% (by weight). Feedstocks need not be chipped, shredded or sorted to
remove metal and glass, and they can be blended. Any mixture of plastics, tires,
manure, paper or yard wastes, construction debris, furniture, hazardous wastes, crop
residues, timber slash, etc., can be converted into synthesis gas, and then to ethanol.
Only the inorganic fraction is not converted. For example, sewage sludge and used
tires could be blended to reduce the average moisture content to 40% or less.
BRI's plants will also operate on natural gas, petroleum and coal --and these
hydrocarbons can be blended with biomass to increase by up to 100% the overall
gallon -per -ton output of the plant.
With nominal ash content of five -to -ten percent of the organic fractions, the process will
normally convert more than 90% of the waste it receives. The remainder, which is non-
hazardous, is discharged from the gasifier to be landfilled or recycled in products like
cement blocks or paving. The net effect is that the BRI process can extend
substantially the effective life of a landfill (and it can reclaim materials already residing
in landfills). This will significantly reduce the amount of valuable and potentially
productive land that must be set aside for this purpose.
The utilities used in operating a BRI plant, with the exception of water, are supplied
internally from the plant's waste heat.
The entire process, from the time the waste material is fed into the gasifier to the
creation of ethanol, takes less than seven minutes. Current biomass ethanol
technologies that use corn kernels or sugar cane as their feedstocks require 36-48
hours for sugar fermentation alone.
This is one of the great strengths of the BRI technology, because this rapid
biochemical conversion, plus the fact that the process creates at least three revenue
sources, makes the technology highly profitable, even without subsidies. Ethanol
futures trading began in May, 2004.
If and when fuel cells become available to power automobiles, the BRI process can
also be used to create hydrogen.
A Typical BRI Renewable Energy Plant
Plant design is governed by the maximum size of today's gasifiers, Therefore, BRI's
plants will be modular and their capacities can be readily expanded. A single module
will combine two gasifiers, each with a capacity of 125-150 tons of waste per day, and
two biocatalytic reactors. Depending upon the feedstocks used, each module will
process some 85,000 tons of biomass annually to produce from 6.8 to 8.0 million
gallons of ethanol, also generating approximately 5 MW of power. The amount of
ethanol and electricity to be produced by any module can be varied according to
energy demand.
Among other configurations, a mid-sized BRI Renewable Energy Plant could process
760,000 tons of municipal solid waste, waste tires and/or wood wastes per year,
producing 50 million gallons of ethanol and generating 35 MW of power, 22 MW of
which is excess to the operation of the plant. The plant would require seven modules
and approximately 16 acres.
The combination of electrical generation and low-priced ethanol production (even if
federal subsidies were to be phased out) makes possible long-term fine and stable
contracts for the generation and sale of "green power' to utilities at rates in thee range
of 5-10 cents per kWh. On the ethanol side, the fact that the BRI process uses
wastes rather than corn kernels means that feedstock costs are as much as $1.00 or
more below the older traditional corn kemel-based sugar fermentation technologies.
Status of Technology
The first bacteria culture to convert synthesis gas into ethanol was isolated by Dr.
James L. Gaddy and his technologists about 15 years ago. Worldwide, some 50
patents have been awarded or are pending for the microorganisms, process and
methods.
BRI has proven the process and bacterial culture, and has been producing ethanol at
its pilot plant for the past four years. Since November, 2003, when BRI added a
prototype Consutech gasifier, the pilot plant has been operating the complete ethanol
production cycle, from waste gasification through the delivery of fuel -grade ethanol in
a single integrated process.
The waste -to -electricity and ethanol filtration elements of the process have been in
commercial operation for a number of years. The technology simply enables the
reconfiguration of these proven technologies in a new and economically viable
process. The technology is now at the point of commercialization. Approximately $15
million in investment, DOE grants and internally generated funds have supported its
development.
In June, 2004, BRI completed for Sealaska Corporation a successful 180 -day steady
state test that included wood waste that had been immersed in salt water for twelve
months or longer. As the feedstock qualities and feed rates were varied during the
tests, the synthesis gas created from this timber slash validated the robust nature of the
bacteria.
In July, 2004, the U.S. Department of Energy announced a grant in the amount of $2.4
million, which is enabling Bioengineering Resources, LLC to test com stover as a
feedstock to create electric power and ethanol using the BRI Process. In so doing, BRI
is investigating the feasibility of locating a com stover ethanol facility next to a
conventional grain alcohol plant in the com belt, and the synergies involved with such
co -location, such as the utilization of waste heat and power from the BRI plant.
Chippewa Valley Ethanol, a Minnesota com producer cooperative, and the engineering
firms of Katzen International and Bums & McDonnell are also participants in the project.
Having studied the technology in depth under full non -disclosure, the Parsons
Corporation, one of the world's leading engineering firms, has entered into a Letter of
Intent to design, construct and operate BRI Energy's plants. They bring to the process
a worldwide reputation and expertise well developed over sixty years.
Katzen International, a Cincinnati-based engineering firm that is renowned for the
efficiency of their ethanol separation and distillation technologies, has been closely
involved with the BRI process during its entire pilot plant phase. Katzen has designed
70 ethanol plants around the world. Their technology and expertise will be utilized to
extract commercial grade ethanol from the fermentation tanks. Katzen will be
responsible for the process design for BRI's plants.
In December, 2004, Parsons Corporation and Katzen completed a feasibility study for
BRI's first commercial plants. Parsons is currently completing the necessary emissions
tests required to design the environmental control systems for the standard BRI plant
module, following which BRI will complete the permitting processes for its initial
commercial plants. These plants will consume municipal solid waste and auto fluff as
their feedstocks.
The combination of Parsons and Katzen provides BRI Energy significant depth in the
design, construction and operation (design-build-operate/DBO) of its plants.
Chemineer, the manufacturer of the fermentation tanks, has guaranteed the ability to
sustain the same environment that was successfully achieved in the pilot plant in their
commercial -sized tanks. All of the equipment utilized in the BRI process is "off-the-
shelf."
The company is now positioned to provide the nation with much-needed relief from the
escalating costs of electric power and liquid energy, and its dependence upon foreign
oil.
Biomass Resources in America
Carbon -based wastes represent one of America's most promising and virtually
untapped domestic energy sources.
More than 1.5 billion tons of municipal solid waste, green waste, sewage sludge,
0
plastics, auto fluff, used tires, agricultural, forestry and other waste products are
generated in the United States each year, 320 million tons of which are readily
available for use in the production of liquid and electric energy.
In addition, America has a three hundred year supply of coal, the combustion of which
represents one of its most destructive sources of industrial pollution. Millions of dollars
are being spent to develop coal gasification projects, but these technologies must still
combust the resulting syngas to generate electricity. The BRI Renewable Energy
Process will create electricity without combustion.
The BRI process could tum states like New York and California into net exporters, rather
than importers, of ethanol. Last year, California consumed some 950 million gallons of
ethanol, only 8 million gallons of which was locally produced. There is enough post -
recycled organic waste available in California to produce two billion gallons of ethanol
per year.
In summary, there is enough readily available biomass in America to produce some
22.5 billion gallons of ethanol and make the nation energy self-sufficient.
The complete development of the Alaskan National Wildlife Reserve would provide
only two percent of America's liquid energy needs. It is realistic to project that the BRI
process could deliver 10% of America's liquid energy requirements from domestically -
produced waste products within ten years and to eliminate the nation's dependence on
foreign oil within twenty years.
Potential of Ethanol
According to an analysis conducted by John Urbanchuk with LECG, LLC, establishing
an 8 billion gallon RFS between 2005 and 2012 would:
• Spark $6 billion (2005 dollars) of new investment to build 4.3 billion gallons of new
ethanol capacity.
• Add nearly $200 billion (2005 dollars) to GDP.
• Generate an additional $43 billion (2005 dollars) of household income for all
Americans.
• Create more than 230,000 new jobs in all sectors of the economy.
• Displace more than 2 billion barrels of crude oil.
• Reduce the outflow of dollars largely to foreign oil producers by $64.1 billion
(2005 dollars).
• Lessen America's dependence on imported oil from an estimated 67.4 percent to
62.3 percent.
Summary
The BRI Renewable Energy Process will:
Make possible the consistent, low-cost generation of electrical energy, while
assisting government agencies in dealing effectively with some of their most
vexing problems—the disposal of municipal solid wastes and sewage sludge, and
the proliferation of landfills.
• Revolutionize the disposal of such organic materials as urban wastes, agricultural
residues, timber slash, wood and plastics.
• Respond to government mandates that call for the introduction of renewable fuels
and the generation of green power.
• Utilize several of the world's most abundant resources to profitably produce fuel -
grade ethanol, a truly sustainable liquid energy source, priced competitively with
gasoline.
• Strengthen the security of nations now dependent on imported oil.
• Provide energy industry employment for the domestic work force.
• Improve the economics of fanning by providing additional income for farmers from
the sale of their agricultural wastes.
• Make an important and lasting improvement to the environment, reducing
greenhouse gases by destroying a meaningful portion of the world's organic
waste stream, and doing so with minimal and manageable ground, air or water
emissions.
TECHNOLOGY SUMMARY
THE BRI PROCESS
The Gasification/Biocatalytic Process
All ethanol processes require two steps: a step to convert raw materials into
intermediates, followed by an ethanol synthesis or production step. Traditional ethanol
processes produce sugars as intermediates, followed by fermentation. An alternative
involves gasification of the raw material to produce synthesis gas. The synthesis gas
results from the breakdown of complex carbon molecules and allows the production of
ethanol in a reactor vessel. There, either a chemical catalyst or a biocatalyst is used
to produce the ethanol.
The chemical catalytic process has been practiced in large scale in South Africa for
many years; but the ethanol specificity of the catalyst is low and a variety of other
alcohols and hydrocarbons are produced, resulting in a low ethanol yield.
The BRI Process is a biocatalytic process that involves the fermentation of syngas.
The biocatalytic process is highly selective or specific and only ethanol is produced,
resulting in high yields, while avoiding the costly additional processing that would
otherwise be required to separate the ethanol from other lower grade products.
Gasification is a commercial technology that has been applied to coal, biomass and a
variety of other carbonaceous materials. Gasification of solids or liquids produces
synthesis gases containing monoxide (CO), hydrogen (1-12) and CO2. BRI has
developed a process to convert these gases into ethanol using a patented
microorganism and process. Since all of the carbon and hydrogen in the raw material
is gasified and can be converted into ethanol, this process has very high yields (at least
0
75 gallons per ton, 150 gallons per ton or more for used tires and other high -BTU
content feedstocks).
Biological Process for Ethanol Production from Biomass
BRI has selected a two-stage gasifier that raises the syngas temperature as high as
2200°F in the second stage to enable cracking of any heavy hydrocarbons to CO and
Hz, maximizing the ethanol yield. There are hundreds of these units in operation with
a demonstrated reliability of 95 percent. The hot gases are then cooled to 98° F and
introduced into the biocatalytic reactor where ethanol is produced. Nutrients are
added to provide for cell growth and automatic regeneration of the biocatalyst. A
dilute, aqueous stream of ethanol is continuously removed through a membrane that
retains cells for recycle to maximize reaction rates. Anhydrous ethanol is produced by
conventional distillation followed by a molecular sieve, using the waste heat from the
process. Water, with nutrients, is recycled from the distillation bottoms back to the
biocatalytic reactor.
Biomass
Sham
Power Aw�'
Na[n<nn @11$17
95+n Ethanol
r
Biological Process for Ethanol Production from Biomass
Anhydrous
Ethanol
The process is simple and well defined, breaking complex molecules into CO, H2 and
CO2, and then reconstructing them back into a single product. Ambient temperature and
pressures are used, and capital and energy costs are minimized. The primary
disadvantages of most biological processes are slow reaction rates and the requirement
for sterilization, neither of which area factor in the BRI technology. For example, the
typical sugar fermentation requires 36-48 hours. Reactor design for the syngas
fermentation has been studied extensively in our laboratories and fermentation times of
a few minutes have been achieved. Also sterilization is not necessary, since the CO in
the syngas eliminates most contaminants.
Co -Generation Of Power
The cooling of the syngas (from as high as 2200° to approximately 1000) before it is sent
to the fermentation vessel creates the opportunity to produce steam and generate
electricity. The primary requirement is that installation of a high pressure steam boiler
rather than normal low pressure equipment.
The quantity of heat from the hot syngas is somewhat dependent upon the gasified
selected and the quantity and temperature of the syngas. In general, this source can
supply 50 M BTU (as steam) per gallon of ethanol produced. The normal design of
about 75 percent would provide 76 M BTU (as syngas) per gallon of ethanol produced.
With conversion efficiencies of about 30 percent, this process will produce about 1.3
MW per million gallons of ethanol, after supplying the internal energy requirements of
the process.
Turbine exhaust steam can then be used as a source of heat for ethanol purification,
feedstock drying, air pre -heating, etc.
Environmental Considerations
The BRI Renewable Energy Process is environmentally superior to any other
technology currently being utilized to dispose of organic wastes, create fuel or produce
electric power. It will destroy organic wastes before they can decompose and produce
electricity without combustion, thus reducing both the need for landfills and multiple
sources of greenhouse gases, COs and methane.
Further, BRI's patented microorganism (the breakthrough element that makes the
entire process possible) is anaerobic, meaning that it dies when exposed to the
atmosphere. It has a Biosafety Level 1 health hazard rating (the lowest possible for
microorganisms). The entire recycling and energy production process creates no
environmental hazards, ground or water contamination, and minimal air emissions.
Emission Sources
There are four sources of emissions from the gasification and energy production
processes: the solid ash from the gasifier, the residues resulting from the scrubbing of
the synthesis gas, a liquid purge from the bioreactor and the minimal emissions that
could result from the secondary production of electricity. Gasification is not
incineration. Gasification occurs in a reducing atmosphere, without production of NO,,
SO„ dioxins or other pollutants. The gasifier ash (inorganic fraction) is non-toxic, with
component concentrations well below EPA requirements, and has been disposed of in
non -hazardous landfills for years.
Gasification
10
There are no air emissions (zero emissions) from the gasification step, as the
synthesis gas does not enter the atmosphere when it leaves the gasifier. Further,
electricity can be produced without combustion. The syngas is cooled, "scrubbed,"
treated through activated carbon filtration, and then fed directly to the bacteria culture.
The gas produced at the high secondary temperature is essentially free of
hydrocarbons. The synthesis gas is scrubbed to remove any residual components
and these gases have been shown to be non-toxic or inhibitory to the biological
culture.
Electricity Generation
Waste heat from the cooling of the synthesis gases is used to create high temperature
steam. There is no combustion associated with this step of the electricity generation
process.
The syngas gas remaining after passing through the bioreactors (less than 15%)
contains a high percentage of marketable hydrogen. The technology could also
additionally use the remainder gas to create ammonia for the production of fertilizer.
Alternatively, this syngas could be mixed with natural gas and combusted to produce
additional high temperature steam, but as the synthesis gas will already have been
scrubbed and will have passed through activated carbon filtration, it will bum 70%
cleaner than the natural gas.
Waste Streams
Inorganic Material
Inerts such as metals or glass will be ejected for recycling or landfilling after the first
stage of thermal gasification. By weight, these will comprise approximately 12.5% of
the materials found in municipal solid waste.
Ash
Only 5% of the organic material will remain as a non -hazardous ash following the
gasification process. This ash can be used in such products as building blocks or
paving, or it could be placed in a sanitary landfill.
Wastewater
The syngas is "scrubbed" prior to entering the biocatalytic reactor.
Scrubber water will contain chlorides and sulfides, which are neutralized before
discharge. BRI will pre -treat the waste stream before it is recycled or sent to a public
wastewater treatment plant. The metals removed during this common industrial
process will either be recycled or landfilled, which would have occurred anyway if the
BRI process did not exist.
Bioreactor Purge
11
The liquid purge from the bioreactor will contain spent cell components and nutrients,
which can be sold as protein for animal feed.
Environmental Impact.
The widespread application of this novel technology can have significant positive
environmental impact in many areas. Landfills for MSW are rapidly becoming filled,
requiring longer and longer transportation routes and higher costs. Land application of
biosolids and animal wastes is coming under increased scrutiny to reduce leaching
and runoff. These negative -cost raw materials are ideal candidates for conversion into
ethanol and power, eliminating the environmental problems with current disposal
methods.
Most electric power and liquid fuel is produced from fossil fuels today, with attendant
emissions of CO2. Landfilling and land application also result in the greenhouse
gases, CO2 and methane. A ton of coal burned to produce electricity produces about
2.4 tons of CO2. A ton of dry biomass placed in a landfill will produce, over time, about
1.2 tons of mixed CO2 and methane. The collection and suitable disposal of this CO2
is the subject of intensive research today. One viable solution, perhaps the only
realistic long-term solution, is the substitution of biomass as fuel, with the subsequent
re -assimilation of CO2 as biomass through photosynthesis. For example, if the
biomass that is landfilled or plowed under as agricultural residue were diverted to an
ethanol plant, one ton would produce 82 gallons of ethanol and about 165kWh of
electricity, reducing CO2 by a net amount of about 40 percent. This comparison does
not include the CO2 re -assimilated as biomass. When added, the result is that each
ton of biomass used to produce ethanol results in the net reduction of about one ton of
CO2 produced from coal or gas fired power production, auto emissions, etc.
Ethanol, blended with gasoline has been shown to reduce auto emissions and, as a
result, oxygenated fuels have been mandated in most metropolitan areas. Traditional
ethanol production methods have been criticized for air emissions from drying of
biosolids for animal feed. It should be noted that the gasification / fermentation
process does not include such a drying step. It is also argued that ethanol from grain
is not renewable and that more energy is consumed than produced, when the energy
for farming, production, etc. is considered. The gasification/fermentation process
utilizes urban wastes, agricultural residues and other wastes, and generates all its own
energy and exports electricity and steam. Therefore, no new external energy is
required in the BRI Process.
James L. Stewart
Vice President & Director of Marketing
BRI Energy LLC
12
3142 Brookdale Road,
Studio City, Califomia 91604-4207
323-650-5095; 818-261-2599 (mobile)
Please visit BRI's web site at: www.bneneMy.com
13