Landfill gas recovery
AssigneeAcrion Technologies, Inc.
InventorsLawrence A. Siwajek, W. Jeffrey Cook, William R. Brown
Life of this patent
Estimating the term…
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.
Claims33
A process for separating carbon dioxide from a landfill gas feed stream containing carbon dioxide, methane and trace contaminants of relatively higher boiling gases, comprising the steps
- compressing the landfill gas feed stream and removing water therefrom to produce a dehydrated gas stream containing said methane, carbon dioxide and trace contaminants,
- introducing said dehydrated gas stream into an absorption column means for absorbing said contaminants with a carbon dioxide absorbent primarily comprising said carbon dioxide present in said landfill gas stream,
- withdrawing from said absorption column means, at a first location, a spent absorbent stream containing no more than about 35% of the carbon dioxide contained in the landfill gas feed stream and substantially all of said gas contaminants, withdrawing from said absorption column at a second location above said first location, a carbon dioxide product stream substantially free of contaminants containing a substantial portion of the carbon dioxide originally present in said landfill gas feed stream, and
- also withdrawing from said absorption column means a methane product stream substantially free of said contaminants and containing most of the methane originally contained in said landfill gas feed stream.
A process for separating carbon dioxide from a landfill gas feed stream containing carbon dioxide, methane and trace contaminants of relatively higher boiling gases comprising the steps of:
- compressing the landfill gas feed stream and removing water therefrom to produce a dehydrated gas stream containing said methane, carbon dioxide and trace contaminants,
- introducing said dehydrated gas stream into an absorption column for absorbing said contaminants with a carbon dioxide absorbent comprising a portion of said carbon dioxide present in said landfill gas stream, and
- withdrawing from said absorption column, at a first location, a spent absorbent stream comprising no more than about about 35% of the carbon dioxide contained in the landfill gas feed stream and substantially all of said gas contaminants, withdrawing from said absorption column, at a second location above said first location, a side product stream containing a substantial portion of the carbon dioxide originally contained in said landfill gas feed stream, and withdrawing from said absorption column a methane product stream containing most of the methane originally contained in the landfill gas feed stream.
A process for separating carbon dioxide from a landfill gas feed stream containing carbon dioxide, methane and trace contaminants of relatively higher boiling gases comprising the steps of:
- compressing the landfill gas feed stream and removing water therefrom to produce a dehydrated gas stream containing said methane, carbon dioxide and trace contaminants,
- introducing said dehydrated gas stream into a first absorption column for absorbing said contaminants with a carbon dioxide absorbent comprising a portion of said carbon dioxide present in said landfill gas feed stream,
- withdrawing from said first absorption column absorber, at a first location, a spent absorbent stream comprising no more than about about 35% of the carbon dioxide contained in the landfill gas feed stream and substantially all of said gas contaminants, and a combined overhead product stream enriched in methane and containing carbon dioxide to be recovered,
- introducing said combined overhead product stream from said first absorption column, as a feed, into a second absorption column to separate carbon dioxide from methane using a carbon dioxide absorbent to form a bottom product containing methane and a substantial portion of the carbon dioxide originally present in the landfill gas feed stream and a methane product stream substantially free of said contaminants and containing most of the methane originally present in the landfill gas stream.
Dependencies are inferred from the claim text.