High temperature size selective membranes. Final report, September 1992--March 1995
Availability of a high temperature size selective membrane capable of separating hydrogen from carbon dioxide and other gases is seen as highly desirable from an economic perspective. Preparation of such a membrane is technically very difficult due to the limitations that the high temperature places on materials selection. We have prepared high temperature membranes as thin film composites of a porous Blackglas{trademark} support and a carbon molecular sieve selective film. Porous Blackglail{trademark} supports have been prepared by pyrolysis of a formed mixture of Blackglas{trademark} B-staged precursor and short Carbon fibers. Such supports have the necessary smoothness for use as a membrane support, good mechanical properties, and an appropriate pore size distribution. These supports can be made either in flat sheet form or in a tubular configuration. A carbon molecular sieve layer can be added to the support by repeated coating/pyrolysis with a dilute solution of precursor polymer. The preferred precursors are polyimide or polyamic acid. Crack formation is observed after the first pyrolyses, but these cracks are repaired during later pyrolyses. The final membrane thickness is only 2.5 {mu}m. The permeation flux of the membrane for hydrogen ranges from 8.1 x 10{sup -5} at room temperature to 3.0 x 10{sup -3} cm{sup 3} (STP) cm{sup -2} sec{sup -1} cmHg{sup -1} at 717{degrees}C, and the selectivity for hydrogen over nitrogen from 2.8 to 3.8, and a selectivity for hydrogen over carbon dioxide of 2.4. This selectivity is close to the Knudsen diffusion limit. In a companion study, unsupported carbon molecular sieve films were also prepared under pyrolysis conditions similar to those used for the supported film. Hydrogen adsorption porosimetry at 19.7{degrees}K was used to show that, under appropriate activation or pyrolysis conditions, such films can be prepared which adsorb hydrogen to a much greater extent than carbon dioxide.
- Research Organization:
- Allied-Signal, Inc., Des Plaines, IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC21-92MC29245
- OSTI ID:
- 374168
- Report Number(s):
- DOE/MC/29245--5261; ON: DE96011349
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of polyimide pyrolysis conditions on carbon molecular sieve membrane properties
Low cost hydrogen/novel membranes technology for hydrogen separation from synthesis gas, Phase 1. Quarterly technical progress report for the period ending June 30, 1987
Low cost hydrogen/novel membranes technology for hydrogen separation from synthesis gas, Phase 1. [Palladium-silver/poly(etherimide), polysulfone/poly(dimethylsiloxane)/poly(ether-esteramide)composite membranes]
Journal Article
·
Sun Sep 01 00:00:00 EDT 1996
· Industrial and Engineering Chemistry Research
·
OSTI ID:376240
Low cost hydrogen/novel membranes technology for hydrogen separation from synthesis gas, Phase 1. Quarterly technical progress report for the period ending June 30, 1987
Technical Report
·
Wed Dec 30 23:00:00 EST 1987
·
OSTI ID:10161737
Low cost hydrogen/novel membranes technology for hydrogen separation from synthesis gas, Phase 1. [Palladium-silver/poly(etherimide), polysulfone/poly(dimethylsiloxane)/poly(ether-esteramide)composite membranes]
Technical Report
·
Wed Dec 31 23:00:00 EST 1986
·
OSTI ID:5045913