The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 10, 2021
Filed:
Mar. 02, 2017
Dow Global Technologies Llc, Midland, MI (US);
Georgia Tech Research Corporation, Atlanta, GA (US);
John Hessler, Ellsworth, ME (US);
William J. Koros, Atlanta, GA (US);
Liren Xu, Pearland, TX (US);
Mark K. Brayden, Baton Rouge, LA (US);
Marcos V. Martinez, Rosharon, TX (US);
Dow Global Technologies LLC, Midland, MI (US);
Georgia Tech Research Corporation, Atlanta, GA (US);
Abstract
The invention is an improved method of making a carbon molecular sieve (CMS) membrane in which a polyimide precursor polymer is pyrolyzed to form a carbon molecular sieve membrane by heating, in a furnace, said polyimide precursor polymer to a final pyrolysis temperature of 600 C to 700 C at a pyrolysis heating rate of 3 to 7 C/minute from 400 C to the final pyrolysis temperature, the final pyrolysis temperature being held for a pyrolysis time of at most 60 minutes in a non-oxidizing atmosphere. In a particular embodiment, the cooling rate from the pyrolysis temperature is accelerated by methods to remove heat. The CMS membranes have shown an improved combination of selectivity and permeance as well as being particularly suitable to separate gases in gas streams such methane from natural gas, oxygen from air and ethylene or propylene from light hydrocarbon streams.