Silica membranes for hydrogen separation in coal gas processing
The general objective of this project was to synthesize permselective membranes suitable for hydrogen separation from coal gas. The specific objectives were: (i) to synthesize membranes by chemical vapor deposition (CVD) of SiO[sub 2] or other oxides on porous support tubes, (ii) characterize the membranes by permeation measurements of various gases and by electron microscopy, and (iii) obtain information about the mechanism and kinetics Of SiO[sub 2] deposition, and model the process of membrane formation. Silica glass and certain other glasses, in dense (nonporous) form, are highly selective to hydrogen permeation. Since this high selectivity is accompanied by low permeability, however, a practical membrane must have a composite structure consisting of a thin layer of the active oxide supported on a porous tube or plate providing mechanical support. In this project the membranes were synthesized by chemical vapor deposition (CVD) of SiO[sub 2], TiO[sub 2], Al[sub 2]O[sub 3] and B[sub 2]O[sub 3] layers inside the walls of porous Vycor tubes (5 mm ID, 7 mm OD, 40 [Angstrom] mean pore diameter). Deposition of the oxide layer was carried out using the reaction of SiCl[sub 4] (or TiCl[sub 4], AlCl[sub 3], BCl[sub 3]) and water vapor at elevated temperatures. The porous support tube was inserted concentrically into a larger quartz tube and fitted with flow lines and pressure gauges. The flow of the two reactant streams was regulated by mass flow controllers, while the temperature was controlled by placing the reactor into a split-tube electric furnace.
- Research Organization:
- California Inst. of Tech., Pasadena, CA (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-89PC89765
- OSTI ID:
- 6759339
- Report Number(s):
- DOE/PC/89765-T12; ON: DE93009670
- Country of Publication:
- United States
- Language:
- English
Similar Records
SiO{sub 2} membranes for H{sub 2} separation in coal gas processing; Quarterly progress report, June 1, 1990--August 31, 1990
TiO sub 2 permselective membranes
Related Subjects
010404* -- Coal
Lignite
& Peat-- Gasification
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400105 -- Separation Procedures
CHALCOGENIDES
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
DEPOSITION
DOCUMENT TYPES
ELECTRON MICROSCOPY
FLUIDS
FUEL GAS
FUELS
GAS FUELS
GASES
HYDROGEN PRODUCTION
MEMBRANES
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
PERMEABILITY
PROGRESS REPORT
SEPARATION PROCESSES
SILICON COMPOUNDS
SILICON OXIDES
SURFACE COATING