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Flow and Diffusion Analysis on the Kinetics of Reduction of Fused Silica in Hydrogen

✍ Scribed by Hiroshi Shirai; Masami Saito; Lian-Sheng Pan; Toshio Abe

Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
259 KB
Volume
160
Category
Article
ISSN
0022-4596

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✦ Synopsis

The kinetics of the reduction of fused silica in hydrogen is studied from the viewpoint of the water vapor generation. The water vapor content in exhaust hydrogen gas is monitored at temperatures ranging from 700 to 12003C. A model of the 6ow and di4usion of water vapor generated at the inner surface of a fused-silica tube in a hydrogen atmosphere is assumed for estimating the water vapor content. Then the reduction reaction rate constants are determined by the best 5t to the measured water vapor concentrations at various temperatures in the range. Arrhenius plots of the rate constants give the activation energy to be approximately 85 kcal/mol, independent of gas 6ow rates and tube diameters, indicating that the reduction rate is reactionlimited. It is worth noting that this study demonstrates the validity of this numerical 6ow and di4usion analysis method on water vapor generation.

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