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US 8,025,715 B2Granted
Process for separating carbon dioxide from flue gas using parallel carbon dioxide capture and sweep-based membrane separation steps
AssigneeMembrane Technology and Research, Inc.
InventorsJohannes G. Wijmans, Timothy C. Merkel, Richard W. Baker
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Abstract
A gas separation process for treating flue gases from combustion processes, and combustion processes including such gas separation. The invention involves routing a first portion of the flue gas stream to be treated to a carbon dioxide capture step, while simultaneously flowing a second portion of the flue gas across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, then passing the permeate/sweep gas to the combustor.
Claims20
A process for controlling carbon dioxide exhaust from a combustion process, comprising:
- (a) performing a combustion process by combusting a mixture of a fuel and air, oxygen-enriched air, or oxygen, thereby creating an exhaust stream comprising carbon dioxide and nitrogen;
- (b) performing a carbon dioxide capture step to remove a portion of carbon dioxide in concentrated form from a first portion of the exhaust stream, thereby creating an off-gas stream from the capture step that is less concentrated in carbon dioxide than the exhaust stream;
- (c) providing a membrane having a feed side and a permeate side, and being selectively permeable to carbon dioxide over nitrogen and to carbon dioxide over oxygen;
- (d) passing a second portion of the exhaust stream across the feed side;
- (e) passing air, oxygen-enriched air, or oxygen as a sweep stream across the permeate side;
- (f) withdrawing from the feed side a carbon-dioxide depleted vent stream;
- (g) withdrawing from the permeate side a permeate stream comprising oxygen and carbon dioxide;
- (h) passing the permeate stream to step (a) as at least part of the air, oxygen-enriched air, or oxygen used in step (a).
5 more elements
Dependencies are inferred from the claim text.