This chapter discusses the development of silica membranes for gas separation at higher temperatures. Using a polymeric gel solution route, tubular micro-porous silica membranes showing high hydrogen permeance and high gas selectivities are prepared. Silica membranes are coated on top of steam-stable γ-Al2O3 intermediate membranes inside a high-quality tubular support. Tube ends are coated with glass giving a gastight changeover between support and membranes. Single dead-end gas permeance measurements performed at temperatures > 300 °C and 4 bar pressure difference showed hydrogen fluxes >1.10-6 mol m-2 s-1 Pa-1 while H2/CO2 permselectivity under these conditions is 80-100. H2/CO2 selectivity increases up to 200 with decreasing pressure down to 1 bar. Membranes are shown to be thermally stable for at least 2000 h at temperatures between 200 and 400 °C. Preliminary water-gas-shift experiments are performed at temperatures above 250 °C and showed higher than equilibrium CO conversion.
|Title of host publication||Carbon Dioxide Capture for Storage in Deep Geologic Formations|
|Number of pages||11|
|Publication status||Published - 1 Dec 2005|