The US$18 million project—called a Green Energy Center by FGE— has three primary phases: the first, to produce power and heat with a microturbine burning LFG methane; second to convert LFG to CNG for vehicles; third to produce methanol for sale and in the production of biodiesel and hydrogen.
Landfill gas is a natural product of the biological decomposition of organic waste. The resulting gas has a variety of chemical components, but at most sites the two principal components are methane (CH4) and CO2, with much smaller amounts of hydrogen sulfides (H2S), inerts and volatile organic compounds (VOCs).
A big problem with LFG projects is the presence of trace components. Typical LFG contains heavy hydrocarbons (both aliphatic and aromatics such as benzene) as well as numerous chlorinated hydrocarbons. These trace compounds are in some cases toxic or hazardous and also cause rapid failure or engine and turbine components. There are now federal statutes which cover landfill emissions.
Acrion’s process removes contaminants from LFG using liquid carbon dioxide obtained directly from the LFG, and produces a stream of contaminant-free methane and CO2.
Contaminants are concentrated in a separate small stream of CO2 for incineration in the landfill flare.
The contaminant-free methane and CO2 stream can be used as medium BTU fuel gas, as a hydrogen source for the fuel cell or as feedstock for methanol synthesis. Further processing can separate CO2 from methane to produce pipeline methane or transportation fuel (compressed or liquefied), and liquid CO2.
(Brookhaven National Laboratory has signed a contract with Acrion to develop a process to produce marketable LNG and liquid CO2 from landfill gas.)
FGE has big plans for the GEC with the Acrion process. The planned LFG processing facilities will:
Generate up to 820 kW of electricity using Ingersoll Rand Micro-turbine technology.
Produce Compressed Natural Gas (CNG) for SWACO’s landfill vehicles and local school buses.
Produce up to 6 million gallons of methanol per year for sale to Mitsubishi Gas Chemical.
Produce up to 75 tons per day of 99.9% pure liquid CO2.
Use LFG-derived methanol to produce up to 10,000,000 gallons of B100 biodiesel in conjunction with a sister biodiesel plant to be built.
Produce Hydrogen gas using Pressure Swing Absorption technology for experimental fuel cell technology development with Ohio State University.