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AssigneesDow Global Technologies LLC, Georgia Tech Research Corporation
InventorsJustin T. Vaughn, Wulin Qiu, William J. Koros, Liren Xu, Mark K. Brayden, Marcos V. Martinez
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The invention is an improved method of making an improved carbon molecular sieve (CMS) membrane in which a precursor polymer (e.g., polyimide) is pyrolyzed at a pyrolysis temperature to form a CMS membrane that is cooled to ambient temperature (about 40° C. or 30° C. to about 20° C.). The CMS membrane is then reheated to a reheating temperature less than the pyrolysis temperature to form the improved CMS membrane. The improved CMS membranes have shown an improved combination of selectivity and permeance as well as stability for separating hydrogen from gas molecules (e.g., methane, ethane, propane, ethylene, propylene, butane, carbon dioxide, nitrogen, butylene, and combinations thereof).
A method of making a carbon molecular sieve membrane comprising,
A method of making a carbon molecular sieve membrane comprising,
The method of any one of the preceding claims, wherein the reheating time is 1 hour to 25 hours.
The method of any one of the preceding claims, wherein the cooling temperature is from 20 to 30° C.
The method of any one of the preceding claims, wherein the reheating atmosphere is an inert gas, nitrogen, air or mixture thereof.
The method of any one of the preceding claims, wherein reheating atmosphere is static for at least a portion of the reheating time.
The method of any one of the preceding claims, wherein reheating atmosphere is flowing.
The method of any one preceding claims, wherein the reheating atmosphere is at atmospheric pressure or above.
The method of anyone of the preceding claims, wherein there is a pressure differential across the carbon molecular sieve membrane such that the reheating atmosphere is drawn through the carbon molecular sieve membrane during reheating.
(canceled)
The method of claim 11, wherein the pressure differential is from 1 to 100 pounds per square inch.
The method of any one of the preceding claims, wherein the precursor polymer is a polyimide.
A method for separating hydrogen from a gas feed comprised of hydrogen and at least one other gas molecule comprising
A method for separating hydrogen from a gas feed comprised of hydrogen and at least one other gas molecule comprising
Dependencies are inferred from the claim text.