Landfill gas recovery
AssigneeAcrion Technologies, Inc.
InventorsLawrence A. Siwajek, W. Jeffrey Cook, William R. Brown
Life of this patent
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Abstract
A process for concentrating and recovering methane and carbon dioxide from landfill gas includes absorption of commonly occurring pollutants using a reduced amount of carbon dioxide absorbent which itself may be an in situ derived and recoverable constituent. Separated methane may be concentrated into a high heating value fuel, and a highly pure food-grade carbon dioxide product may also be recovered. Process streams may be used to provide fuel for compression and refrigeration and/or to regenerate carbon dioxide absorbent.
Claims5
A gas separation process for separating carbon dioxide, methane and trace contaminants contained in a landfill gas feed stream comprising the steps of:
- separating said trace contaminants from said landfill gas feed stream to form a methane product gas stream containing substantially only carbon dioxide, methane and nitrogen,
- introducing said methane product gas stream into an absorption column for contact with a solvent to form a second methane product containing substantially only methane and nitrogen and a carbon-dioxide enriched bottom product containing substantially only solvent and carbon dioxide,
- separating said second methane product by liquefaction into a gaseous overhead liquefaction product comprising a methane and nitrogen mixture and a liquid liquefaction product comprising methane,
- introducing said carbon dioxide-enriched bottom product and said gaseous overhead liquefaction product into a stripper to regenerate the solvent absorbent by forming a solvent bottom product comprising substantially only solvent for use in said absorption column and a stripper top product comprising substantially only carbon dioxide, nitrogen and methane, and
- recycling said solvent bottom product back to said absorption column.
A gas separation process for separating carbon dioxide, methane and trace contaminants contained in a landfill gas feed stream comprising the steps of:
- separating said trace contaminants from said landfill gas feed stream to form a methane product gas stream containing substantially only carbon dioxide, methane and nitrogen,
- introducing said methane product gas stream into an absorption column for contact with a physical absorbent to form a methane-enriched top product containing substantially only methane and nitrogen and a carbon-dioxide enriched bottom product containing substantially only absorbent and carbon dioxide,
- separating said top product by liquefaction into a liquid liquefaction bottom product comprising methane and a gaseous overhead liquefaction product comprising methane and nitrogen in a mixture suitable for use as a fuel in an engine to provide power in said gas separation process, and
- providing the compression and cooling required in the process by use of said overhead liquefaction product.
Dependencies are inferred from the claim text.