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Silica membranes for hydrogen separation in coal gas processing. Final report, January 1993

Gavalas, G. R. (1993) Silica membranes for hydrogen separation in coal gas processing. Final report, January 1993. .

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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.

Item Type:Report or Paper (Technical Report)
Related URLs:
URLURL TypeDescription
Gavalas, G. R.0000-0003-1468-6835
Additional Information:© 1993 U.S. Department of Commerce.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG22-89PC89765
Subject Keywords:Hydrogen Production Membranes Silicon Oxides Fuel Gas Chemical Vapor Deposition Electron Microscopy Permeability Progress Report Separation Processes
Record Number:CaltechAUTHORS:20151105-115204740
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61896
Deposited By: Ruth Sustaita
Deposited On:06 Nov 2015 20:10
Last Modified:03 Oct 2019 09:13

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