Steam reformation of hydrogen sulfide

A modified version of the Sulfur-Iodine cycle, here called the Sulfur-Sulfur Cycle, offers an all-fluid route to thermochemical hydrogen and avoids implications of the corrosive HI-H2O azeotropic mixture: 4I(2(l)) + 4SO(2(l)) + 8H(2)O((l)) <-> 4H(2)SO(4(l)) + 8HI((l)) (120 degrees C) (1) 8HI((l)) + H2SO4(l) <-> H2S(g) + 4H(2)O((l)) + 4I(2(l)) (120 degrees C) (2) 3H(2)SO(4(g)) <-> 3H(2)O((g))+3SO(2)(g) + 1 1/2O(2(g)) (850 degrees C) (3) H2S(g) + 2H(2)O((g)) <-> SO2(g) + 3H(2(g)) (900-1500 degrees C) (4) The key step in the Sulfur-Sulfur cycle is the steam reformation of hydrogen sulfide, which is highly endothermic and has a positive Gibbs free energy change. The steam reformation of hydrogen sulfide was investigated under favorable circumstances (excessive dilution with steam and inert carrier) over a variety of catalytic and non-catalytic settings in a quartz tube. Successful results were obtained by pretreating a molybdenum wire with H2S at high temperature. Apparent Arrhenius parameters for both thermal splitting and steam reformation of hydrogen sulfide were determined. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.