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US 12,594,523 B2Granted
Membrane capture of CO2 from refinery emissions
AssigneeChevron U.S.A. Inc.
InventorsDaniel Chinn, Nitesh Bhuwania, Alice Zunqing He
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Abstract
The present invention is directed to a method of capturing CO2 from a FCC regenerator using select membranes.
Claims20
A method for capturing CO2 produced from a FCC regenerator flue gas comprising,
- (1) cooling and compression of the flue gas to overcome a pressure drop in equipment downstream of the FCC regenerator;
- (2) operating a crossflow membrane at vacuum permeate pressure to remove the bulk of the CO2, followed by a membrane which operates with a counter-current air sweep on the permeate side to further reduce the CO2 amount;
- (3) two stage compression of permeate from the crossflow membrane using vacuum pumps and then in 3 stages of compression to 48 bar;
- (4) liquefying the CO2 from the 3 stages of compression using a CO2 liquefaction unit that liquefies CO2 out the bottom and produces a CO2-rich vapor which is sent to a high-pressure polishing membrane;
- (5) recycling the permeate of the polishing membrane to the liquefaction unit feed while the retentate is recycled directly to the crossflow membrane feed;
- wherein the counter-current air sweep flowrate is adjusted to maintain about the same percentage of excess oxygen as an uncontrolled FCC regenerator.
3 more elements
A method for capturing CO2 produced from a FCC regenerator flue gas comprising,
- (1) cooling and compression of the flue gas to overcome a pressure drop in equipment downstream of the FCC regenerator;
- (2) operating a crossflow membrane at vacuum permeate pressure to remove the bulk of the CO2, followed by a membrane which operates with a counter-current air sweep on the permeate side to further reduce the CO2 amount;
- (3) two stage compression of permeate from the crossflow membrane using vacuum pumps and then in 3 stages of compression to 48 bar;
- (4) liquefying the CO2 from the 3 stages of compression using a CO2 liquefaction unit that liquefies CO2 out the bottom and produces a CO2-rich vapor which is sent to a high-pressure polishing membrane;
- (5) recycling the permeate of the polishing membrane to the liquefaction unit feed while the retentate is recycled directly to the crossflow membrane feed;
- wherein a portion of the combustion air for the FCC regenerator is replaced by the CO2-enriched, oxygen-depleted air sweep from the membrane operating with counter-current air sweep.
3 more elements
Dependencies are inferred from the claim text.