Development of an All-ceramic Module with Silica Membrane Tubes for High Temperature Hydrogen Separation

Abstract

Heat resistant hydrogen selective membranes are desired for use as membrane reactors in low-temperature hydrogen production via the steam reforming of hydrocarbons, which are usually operated over 1000 K. In addition, developing a multi-tubular type of membrane unit that can process more reactants is becoming more and more important in order to realize the practical use of membrane reactors.

In this study, an all-ceramic module consisting of 6 silica membrane tubes with a comparatively large membrane area of around 0.04 m² was fabricated by a counter-diffusion chemical vapor deposition technique. As a result, the H₂/N₂ ideal separation factor and the H₂ permeance of the module were 1300 and 1.9 × 10⁻⁷ mol·m⁻²s⁻¹Pa⁻¹ at 873 K, respectively. In a 1000-hour thermal stability test for the silica membrane module, it was found that the H₂ permeance initially decreased by about 30% and then became steady under ΔP = 0.95 MPa at 773 K.

Keywords:

• Ceramic
• CVD
• hydrogen production
• module
• silica membrane

ACKNOWLEDGEMENTS

This work was performed as a part of the R&D Project for High Efficiency Hydrogen Production/Separation System using Ceramic Membrane funded by NEDO, Japan.

The authors would like to thank Shinji Fujisaki at the Japan Fine Ceramics Center (JFCC) and Yuji Iwamoto at the Nagoya Institute of Technology for their contributions to the TEM observations.