LANDFILL GAS TO LIQUEFIED NATURAL GAS AND LIQUID TRANSPORTATION FUELS

摘要

The U.S. Department of Energy (DOE) estimates that 50% of the waste that is being annually deposited in landfills provides over 270 billion cubic feet of methane. This presents the opportunity of making clean transportation fuels from a sustainable resource, while also mitigating the release of a global warming gas (methane). Over the past several years, DOE’s Office of Freedom Car and Vehicle Technology has been supporting several landfill gas (LFG) to liquefied natural gas (LNG) projects. One of the first projects was at the Arden landfill in Washington, PA where a LNG refueling station has been sited and refuse haulers have been operating on trucked-in LNG. The plan is to install a gas cleanup system and small scale liquefier to make use of the methane being produced at the landfill. Another ongoing project which employs Acrion’s patented CO2 wash technology for contaminant removal is to produce 10,000 gallons of LNG at the Burlington, NJ landfill to test as a vehicle fuel. This paper reviews the findings of these and other LFG to LNG projects and discusses some of the enabling technologies necessary for converting LFG to LNG. It also looks at using bioreactors with Fischer- Tropsch liquid (FTL) technologies for the synthesis of clean liquid fuels. In either case of producing LNG or FTL, market penetration requires a sound business case. Currently, life cycle costs (capital and operation) for both technologies can only be estimated, thus there are risks associated with commercialization. From a fundamental point of view, however, it is being suggested that conventional dry tomb landfills favor the production of LNG or methanol, whereas bioreactors with appropriate water management favor the production of liquid fuels using Fisher-Tropsch technologies.