Membrane CO2 separation process
AssigneeMembrane Technology and Research, Inc.
InventorRichard W. Baker
Life of this patent
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Abstract
Described herein are membrane processes for separating CO2 from flue gas. An exemplary process involves passing a fluid stream including the flue gas across a membrane permeable to CO2 and H2O, removing treated gas from a feed side of the membrane that has less CO2 than the flue gas, and removing permeate from a permeate side of the membrane comprising CO2 and H2O. Suitably, the permeate is removed at a sub-atmospheric vacuum pressure. The permeate is then cooled to remove at least some of the H2O from the permeate and form a smaller volume of H2O-depleted, CO2 enriched permeate.
Claims52
A membrane process to separate CO2 from flue gas, the process comprising:
- passing a fluid stream including the flue gas across a membrane permeable to CO2 and H2O;
- removing treated gas from a feed side of the membrane, the treated gas having less CO2 than the flue gas;
- removing permeate from a permeate side of the membrane at a sub atmospheric pressure between 0.1 to 0.4 bar, the permeate comprising CO2 and H2O;
- cooling the permeate to remove at least some of the H2O from the permeate and form a smaller volume of H2O-depleted, CO2 enriched permeate;
- and
- using a vacuum pump to increase the gas pressure of the smaller volume of H2O-depleted, CO2 enriched permeate to at least about atmospheric pressure.
A membrane process to separate CO2 from flue gas comprising:
- (i) bringing the flue gas to a pressure of 0.8 to 1.5 bar and a temperature of greater than 50° C., wherein the flue gas contains greater than 10 mol % water vapor;
- (ii) passing the flue gas from (i) across a membrane permeable to water and CO2, said membrane having an H2O/CO2 selectivity of greater than 2 and a CO2/N2 selectivity of greater than 10, measured at the operating conditions of the membrane process;
- (iii) removing from the feed side of the membrane of (ii) a treated flue gas stream from which at least 50% of the CO2 content of the flue gas has been removed;
- (iv) removing from the permeate side of the membrane in (ii) at a pressure of 0.1 to 0.4 bar, a permeate gas enriched in CO2 and H2O;
- (v) cooling the permeate gas from (iv) to a temperature of 5-30° C. to condense a portion of the H2O content of the permeate gas and so lowering the H2O concentration of the permeate gas to produce a water-depleted permeate gas;
- (vi) separating the condensed water from the water-depleted permeate gas;
- and
- (vii) using a vacuum pump to bring the water-depleted permeate gas from (v) to atmospheric pressure or above.
Dependencies are inferred from the claim text.