Hydrogen Production by Hydrogen Iodine Decomposition Assisted with Membrane

Abstract

AbstractIn order to improve the low equilibrium of the HI decomposition, a membrane reactor assisted with H2 permselective membrane was developed. Silica membranes and stable HI decomposition catalysts have been investigated for the membrane reactor. Silica membranes were prepared on porous ceramic tubes by using a counter diffusion chemical vapor deposition. The membrane deposited at 450 °C showed the H2 permeance of 5.0 × 10–7 mol m−2 s−1 Pa−1 with the H2/HI permeance ratio of 6820. For HI decomposition catalysts, Pt–Rh/TiO2/active carbon showed high conversion and stability. This catalyst shows HI decomposition conversion, ca.95% of the equilibrium conversion which was sustained up to 200 h. Finally, membrane reactor test was conducted to improve the HI decomposition reaction at 400 °C. The conversion was stable at about 0.48 by the assist with the H2 permselective membrane and the conversion was higher than the equilibrium one (0.22).KeywordsHydrogen permselective membraneChemical vapor depositionPt catalystCatalyst stabilityMembrane reactor