Catalyzed thermal decompositon of H 2SO 4 and production of HBr by the reaction of SO 2 with Br 2 and H 2O

Abstract

Decomposition of H 2SO 4 and production of HBr have been studied as a part of the research and development of the thermochemical hydrogen production from water. The catalytic activities of various metals and metal oxides on a porous alumina support were studied for the thermal decomposition of sulfuric acid in a fixed bed reactor. A Pt-Al 2O 3 catalyst gave a conversion of SO 3 close to the equilibrium at temperatures from 1073 to 1173 K and at a space velocity below 10 000 h −1. It was also found that metal oxide catalysts such as CuO and Fe 2O 3 were as active as the Pt catalyst. To prepare SO 2-free HBr gas by the reaction between SO 2, Br 2 and H 2O, vapor-liquid equilibrium determinations for SO 2/Br 2/HBr/H 2SO 4/H 2O system were carried out at 298 K under atmospheric pressure. The unconverted SO 2 can be effectively removed by contacting the effluent gases with a HBr saturated aqueous solution containing an excess of Br 2.