OPERATING A FUEL CELL USING LANDFILL GAS EPA/6QO/A-96/128
C. E. Trippel, Northeast Utilities Service Company
J. L. Preston, Jr. and J. C. Trocciola, International Fuel Cells Corporation
R. J. Spiegel, U.S. Environmental Protection Agency
An ONSI PC25™, 200 kW (nominal capacity) phosphoric acid fuel cell operating on landfill gas
(LFG) is installed at the Town of Groton Flanders Road landfill in Groton, Connecticut. This
joint project by the Connecticut Light & Power Company (CL&P) which is an operating
company of Northeast Utilities, the Town of Groton, International Fuel Cells (IFC), and the
United States Environmental Protection Agency (EPA) is intended to demonstrate the viability
of installing, operating, and maintaining a fuel cell operating on LFG at a landfill site. The
goals of the project are to evaluate the fuel cell and gas pretreatment unit (GPU) operation, test
modifications to simplify the design, and demonstrate the reliability of the entire system.
In 1990, the EPA contracted with IFC to design and build a landfill GPU that would allow LFG
to be used by a fuel cell. Upon successful demonstration of the GPU, the fuel cell was installed
at the Penrose Landfill in Los Angeles to demonstrate the system operation. The energy
recovery system operated for approximately 3 months, concluding operations in February 1995.
In order to verify operation on a different composition LFG and in different climatic conditions,
the energy recovery system was shipped to the East Coast. Discussions between all parties
resulted in the Town of Groton landfill being chosen as a site to continue operation of the fuel
cell and GPU system. The EPA is the current owner of the fuel cell and the GPU and is
providing technical expertise for the project. CL&P is the funding source for the project and is
providing the engineering, design, and construction for the installation as well as the operation
and maintenance for the 12-18 month demonstration period. IFC is providing technical
expertise for the operation of the fuel cell and GPU system. The Town of Groton is providing
the site as well as the collected LFG and operation of an existing LFG flare at no cost to CL&P.
The LFG is collected from an 18.2 ha (45 acre) closed landfill. Based on the estimated volume
of solid waste in the Groton landfill, a calculated 5.8 million m1 (204 million ft1) of LFG would
be produced annually. Prior to the installation of the fuel cell system at Groton, the LFG was
collected and burned in a flare at a rate of approximately 0.189 m'/s (400 cfm). The fuel cell
system uses a maximum of 0.0378 mVs (80 scftn) of landfill gas while the remaining gas
continues to be burned by the flare. Where LFG is emitted into the atmosphere without recovery
and use, methane has a global warming potential much greater than that of carbon dioxide
(CO2). Some of the non-methane constituents of LFG, such as hydrogen sulfide (HjS), are
odoriferous and potentially harmful to the environment.
The fuel cell emissions are primarily water vapor and CO2. Emissions of nitrogen oxides (NOX)
and sulfur dioxide (SOJ, which result from the combustion of LFG, are virtually eliminated.
Due to its higher efficiency, the quantity of CO3 emitted from the fuel cell is less than the
amount created through combustion conversion electrical generators such as the combustion
turbine and internal combustion engine. A comparison of typical emission rates is:
Typical Emission Rates (g/kWh)
Combustion Internal
Turbine Combustion Engine Fuel Cell
NOX 0.694 0.417 0.004
SO2 0.077 0.054 0
CO2 889.041 621.421 435.449
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TRIPPEL ET AL.
2
System Description at the Groton Landfill
The LFG is collected from the closed and capped landfill through a series of wells and is drawn
out of the landfill by the flare blower. This maintains an absolute pressure of 99.8 kPa (14.5
psia) on the collection system. An LFG compressor draws LFG from a collection header and
compresses the gas to 276 kPa (40 psig) for use in the GPU. Two H,S absorbers, using activated
carbon as the absorbing medium, are installed on the suction side of the compressor to remove
the H,S from the gas stream prior to compression. A moisture separator prior to the EL.S
absorbers removes any bulk moisture present in the gas. The H,S absorbers are installed in a
parallel/series arrangement where normal operation is in series but either absorber can be
removed from service while the other is in service. This is useful for carbon changeout during
operation or testing the removal effectiveness of an individual absorber.
The gas is discharged from the gas compressor and into the GPU where moisture and volatile
organic compounds (VOCs) including sulfides and halogenated compounds are removed. The
GPU has dual cleanup trains so when one train is in service cleaning the gas the other is being
regenerated with a portion of the cleaned gas. The regeneration gas, in the quantity of 0.0118
mVs (25 scfrn), is combusted in an enclosed flare. The cleanup train consists of an alumina plus
mole sieve dryer vessel which removes the moisture from the gas, a carbon vessel which absorbs
hydrocarbons and VOCs, and a refrigeration unit and heat exchanger which are used to cool the
gas to 274.3 K (34°F) prior to entering the cleanup train. The gas leaves the GPU consisting of
methane, C02, and trace amounts of nitrogen and oxygen. The dew point of the gas is 244.3 K (-
20°F). The specific composition of the Groton LFG leaving the GPU is:
Methane- 57.1%
Carbon dioxide-41.0%
Nitrogen- 1.5%
Oxygen - 0.4%
The fuel cell has been modified for operation on LFG to accept the higher flow rate required
because of the reduced methane content in the LFG. These modifications include a larger fuel
control valve and fuel control venturi plus resizing of two fixed orifices. Minor modifications
were also made to the control settings.
Site Layout
Figure 1 is a site layout plan that shows the equipment configuration. The total site
encompasses an area 13.12 m (43 ft) wide by 41.15 m (135 ft) long and is enclosed by a chain
link fence. Located at the south end of the site are the existing LFG flare and a newly installed
underground storage tank to collect condensate that comes from the landfill with the gas as well
as from the GPU. The GPU control room houses the GPU control panel, refrigeration unit purge
air compressor, nitrogen bottles for actuating the GPU pneumatic valves, and project
documentation. The GPU flare is used to combust the regeneration ps. The gas pretreatment
unit building is a pre-engineered building with aluminum sided and insulated walls and roof.
The space inside the building is considered a Class 1, Division 2 location, and all electrical
equipment and fixtures are explosion proof. Enclosed in the gas pretreatment unit building is the
LFG moisture separator, HL.S absorber vessels, gas compressor, GPU, and refrigeration unit. A
combustible gas detector is used to monitor the interior atmosphere and ultimately shut down the
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TRJPPEL ET AL.
3
gas compressor if gas is detected. A compressed natural gas (CNG) bottle rack is required to
supply start up burner fuel for the fuel cell and for the GPU flare. The fuel cell and cooling
module are in the standard configuration for a typical installation. A nitrogen bottle rack
external to the fuel cell is used to increase bottle capacity and facilitate bottle changeout. The
switchgear contains the distribution bus and breakers for the fuel cell and all other site
equipment. The step-up transformer takes the 480 V power from the fuel cell output and
increases it to 13,800 V for use on the utility grid. The equipment and site layout are designed
for unmanned operation. Remote data monitoring of the fuel cell and GPU controller will be
utilized.
Project Status
Construction was completed in mid-June 1996, and system start-up and testing was in progress
at the time of the submittal of this paper in late August 1996. Prior to start-up of the fuel cell,
the GPU was started and operated for 200 hours, and gas quality suitable for fuel cell operation
was verified. Operation of the fuel cell at the Groton site on landfill gas has been achieved with
an output of 165 kW obtained to date. The power generated is enough to supply over 100 homes
and is fed into the local utility grid. Continued testing and refinement of the system is expected
to achieve a continuous net fuel cell output of 140 kW.
Conclusion
The operation of fuel cells on landfill gas presents an opportunity to use a waste gas that is
harmful to the environment to generate electricity more cleanly and efficiently than other
methods currently used. The use of other bio gases, such as from waste water treatment plants
and livestock wastes, in fuel cells is possible as a result of the work performed using LFG as a
fuel. This project brings bio gas conversion using fuel cells one step closer to commercial
application.
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77W¥>£1 ET AL.
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NRMRL-RTP-P-160
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completin
1. REPORT NO.
EPA/600/A-96/128
2,
3. R)
4. TITLE AND SUBTITLE
Operating a Fuel Cell Using Landfill Gas
5. REPORT DATE
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
C.E.Trippel (NUS); J.L.Preston, Jr. and J. C.
Trocciola (IFC); and R. J. Spiegel (EPA)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Northeast Utilities and International Fuel Cells
Service Co. Corp.
PC Box 270 195 Governors Hwy
Hartford, CT 06141 S. Windsor, CT 06074
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D1-0008 (IFC)
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Published paper; 5-9/96
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES APPCD project officer is Ronald J. Spiegel, Mail Drop 63, 919/
541-7542. Presented at Fuel Cell Seminar, Orlando, FL, 11/17-20/96.
i6. ABSTRACT
paper discusses operating a 200- kW phosphoric acid fuel cell using
landfill gas (LFG) in Groton, Connecticut. The project is intended to demonstrate the
viability of installing, operating, and maintaining a fuel cell operating on LFG at a
landfill site. The goals of the project are to evaluate the fuel cell and gas pretreat-
ment unit (GPU) operation, test modifications to simplify the design, and demon-
strate the reliability of the system. The operation of the fuel cell on LFG presents
an opportunity to use a waste gas that is harmful to the environment to generate elec-
tricity more cleanly and efficiently than other methods currently used. The use of
other bio gases, such as from waste water treatment plants and livestock wastes, in
fuel cells is possible as a result of the work performed using LFG as a fuel.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c, COSATI Field/Group
Pollution
Fuel Cells
Earth Fills
Phosphoric Acids
Exhaust Gases
Pollution Prevention
Stationary Sources
Landfill Gas
13 B
10 B
13 C
07B
21B
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
20. SECURITY CLASS (Thispage}
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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