CO2 rejection from natural gas
First Claim
1. A pressure swing adsorption (PSA) process for the separation of a single gas from a mixture of gases which comprises:
- a) passing a feed stream comprising said mixture in contact with an adsorbent which is selective for said single gas in a PSA unit so as to preferentially adsorb said single gas and produce a product depleted in said single gas and a low pressure purge stream having a higher concentration of said single gas than said mixture;
b) co-currently depressurizing said PSA unit to form a recycle stream having a lower concentration of said single gas than said purge stream, said recycle stream having a pressure less than said product stream, but greater than said purge stream; and
c) recycling said recycle stream to said feed stream.
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Accused Products
Abstract
An improved pressure swing adsorption process is provided for removing or separating a gas from a mixture of gases. The PSA process comprises selectively adsorbing a gas from the mixture to form a product gas having a reduced concentration of the selectively adsorbed gas and a low pressure purge stream containing a higher level of the selectively adsorbed gas than contained in the mixture. During regeneration of the adsorbent a co-current recycle stream is provided which has a pressure less than the product stream, but greater than the purge stream for recycle to feed so as to minimize loss of the product gas to purge. The PSA process is particularly useful for removing carbon dioxide from coal bed methane.
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Citations
22 Claims
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1. A pressure swing adsorption (PSA) process for the separation of a single gas from a mixture of gases which comprises:
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a) passing a feed stream comprising said mixture in contact with an adsorbent which is selective for said single gas in a PSA unit so as to preferentially adsorb said single gas and produce a product depleted in said single gas and a low pressure purge stream having a higher concentration of said single gas than said mixture;
b) co-currently depressurizing said PSA unit to form a recycle stream having a lower concentration of said single gas than said purge stream, said recycle stream having a pressure less than said product stream, but greater than said purge stream; and
c) recycling said recycle stream to said feed stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A pressure swing adsorption (PSA) process for the separation of carbon dioxide from a mixture of the same with methane which comprises:
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a) passing a feed stream comprising said mixture in contact with a carbon dioxide-selective adsorbent in a PSA unit so as to preferentially adsorb carbon dioxide and produce a methane-rich product stream and a low pressure purge stream having a higher molar concentration of carbon dioxide than said mixture;
b) co-currently depressurizing said PSA unit to form a recycle stream rich in methane, said recycle stream having a pressure less than said methane-rich product stream, but greater than said purge stream; and
c) recycling said recycle stream to said feed stream. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification