Method of making carbon molecular sieve membranes
US11084000B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 2, 2017 |
| Grant date | Aug 10, 2021 |
| Priority date | — |
| Expiry date | Dec 7, 2037 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02C20/40
- WIPO fieldChemical engineering
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.