Patent ID: 8211211
Filing Date: 2012-07-03
Classification: B01D,Y02E

Abstract:
1. A method for producing a methane product gas from a feed gas comprising a mixture of methane, carbon dioxide, nitrogen, oxygen, and water vapor, wherein the methane product gas is enriched in methane compared to the feed gas, which comprises the steps of: (a) a first pressure swing adsorption (PSA) stage wherein carbon dioxide and water vapor are removed from said feed gas to produce a first intermediate product stream enriched in methane, oxygen, and nitrogen, compared to said feed gas; (b) a second temperature swing adsorption (TSA) stage, wherein carbon dioxide and water are removed from said first intermediate product stream to produce a second intermediate product containing less than about 35 ppm carbon dioxide and less than about 35 ppm water vapor; and (c) a third PSA stage wherein nitrogen and oxygen are removed from said second intermediate product to produce said methane product gas having less than about 50 ppm carbon dioxide, less than about 0.5 ppm water vapor, less than about 5% nitrogen, and less than about 1% oxygen.