Research and Development EPA/600/SR-95/155 April 1996

E AP

Demonstration of Fuel Cells to

Recover Energy from Landfill

Gas - Phase II. Pretreatment

System Performance

Measurement

The report describes Phase II of a

demonstration of the utilization of commercial phosphoric acid fuel cells to

recover energy from landfill gas. This

phase consisted primarily of the construction and testing of a Gas Pretreatment Unit (GPU) whose function is to

remove those impurities from landfill

gas which are detrimental to the fuel

cell. The GPU has been successfully

tested at a landfill-to-energy facility in

Los Angeles (Sun Valley), California.

The GPU successfully removed the sulfur and halogen compounds contained

in the landfill gas to a level significantly below that specified for use with

the phosphoric acid fuel cell. During a

challenge test in which dichlorodifluoromethane (Refrigerant 12) was intentionally injected into the process stream

during an 8-hour period, the exit concentration of Refrigerant 12 was below

the limit of detection and below the

specified value for the fuel cell.

This Project Summary was developed by EPA's National Risk Management Research Laboratory's Air Pollution Prevention and Control Division,

Research Triangle Park, NC, to announce key findings of the research

project that is fully documented in a

separate report of the same title (see

Project Report ordering at back).

Overview

International Fuel Cell Corporation (IFC)

has completed Phase II of a U.S. Environmental Protection Agency (EPA) demonstration of the utilization of commercial

phosphoric acid fuel cells to recover enProject Summary

ergy from landfill gas. This phase of the

program consisted primarily of the construction and testing of a Gas Pretreatment Unit (GPU) whose function is to remove those impurities from landfill gas

which are detrimental to the fuel cell.

The GPU has been successfully tested

at a landfill site located in Los Angeles

(Sun Valley), California. The site is operated by Pacific Energy Corporation as a

landfill-to-energy facility. The GPU successfully removed the sulfur and halogen

compounds contained in the landfill gas to

a level significantly below that specified

for use with the phosphoric acid fuel cell.

During a challenge test in which dichlorodifluoromethane (Refrigerant 12) was

intentionally injected into the process

stream during an 8-hour period, exit concentration of Refrigerant 12 was below

the limit of detection and below the specified value for the fuel cell.

The GPU was constructed by IFC at its

facility in South Windsor, Connecticut. Construction of the unit was completed in February 1993. Upon completion of construction, the unit was evaluated at the South

Windsor facility using nitrogen as the test

gas. The unit successfully completed the

16-hour control test verifying that rated

flows, pressure, and temperature were

achieved. After the test, the unit was

shipped to the landfill site in Los Angeles,

California, where it was installed in April

1993.

The GPU system is shown schematically in Figure 1. The system consists of a

number of fixed beds and condensers/

heat exchangers. A functional description

of the major elements of the GPU is conUnited States National Risk Management

Environmental Protection Research Laboratory

Agency Research Triangle Park, NC 27711

J.S. Trocciola
2

tained in Table 1. The unit has been tested

on landfill gas at the site, and Table 2

compares the measured sulfur and halide

contents of the gas produced by the GPU

to the specification value. The data verify

that the GPU reduces the sulfur and halide contents of landfill gas to a concentration lower than required by the fuel cell

power plant. The data also show that liquids do not condense in the low temperature cooler. However, that cooler reduces

the temperature of the landfill gas prior to

its introduction into the carbon bed, increasing the capacity of the carbon bed

for the sulfur and halogen compounds.

For system simplification in the future, it

may be beneficial to eliminate the low

temperature cooler and accept any reduction in carbon bed capacity. Based on the

favorable results of the GPU testing, the

EPA directed IFC to proceed into Phase

III of the program which entails characterizing the performance (i.e., emissions, efficiency, and power output) of the commercial phosphoric acid fuel cell power

plant when operating on landfill gas which

has been purified by the GPU.

Low

Temperature

Cooler

Carbon

Bed

(Adsorption

Cycle)

Particulate

Filter

Cooler

Condenser

H2

S

Removal

Landfill Gas

▼

▼

▼

▼

▼

▼

▼

▼

Clean

Landfill

Gas to

Fuel

Cell

Regeneration

Gas

▼

▼

Carbon

Bed

(Regeneration

Cycle)

▼

To

Flare

Dryer

▼

Bed

(Regeneration

Cycle)

▼

To

Flare

▼

Dryer

Bed

(Adsorption

Cycle)

Figure 1. Landfill gas pretreatment system.

a Measured by gas chromatography/flame photometric detector by EPA Methods 15, 16, and 18.

b Measured by gas chromatography/mass spectroscopy by EPA Method TO-14.

Total Sulfur (as H2

S)a < 0.047 <3

Total Halides (as Chloride)b < 0.032 <3

H2S Removal Bed Remove H2S No

Cooler/Condenser Remove Water, Hydrocarbons Not Applicable

Dryer Bed Remove Water to -50°C Dew Point Yes

Low Temperature Cooler Cool Carbon Bed Not Applicable

Carbon Bed Remove Organic Sulfur and Halogen Yes

Compounds

Filter Remove Particulates No

Table 1. GPU Component Functions

Component Function Regenerable

Table 2. GPU Sulfur and Halide Contaminant Removal Performance vs. Specification

GPU Exit (ppmV) Specified Value (ppmV)
3

EPA/600/SR-95/155

United States

Environmental Protection Agency

National Risk Management Research Laboratory (G-72)

Cincinnati, OH 45268

Official Business

Penalty for Private Use $300

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

J.S. Trocciola is with International Fuel Cells Corp., South Windsor, CT 06074.

Ronald J. Spiegel is the EPA Project Officer (see below).

The complete report, entitled "Demonstration of Fuel Cells to Recover Energy from

Landfill Gas - Phase II. Pretreatment System Performance Measurement,"

(Order No. PB96-103 601; Cost: $35.00, subject to change) will be available only

from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at:

Air Pollution Prevention and Control Division

National Risk Management Research Laboratory

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711