Study of the reaction of high-temperature H2S decomposition on metal oxides (γ-Al2O3, α-Fe2O3, V2O5)

Experimental study of the reaction of heterogeneous decomposition of the hydrogen sulfide on bulk oxides gamma-Al2O3, alpha-Fe2O3 and V2O5 in the interval of temperatures 500-900degreesC have been performed. Reaction orders by H2S for gamma-Al2O3 and V2O5 are 2.0, and for alpha-Fe2O3 - 2.6; effective activation energies are respectively 72, 94 and 103 kJ/mol. Using the ESDR and XRD methods, it is shown that in the course of hydrogen sulfide decomposition reaction, the reduction of transition metal oxide catalysts (alpha-Fe2O3 and V2O5) and also the formation of sulfides under the influence of reaction media proceed. Interaction of hydrogen sulfide with aluminum oxide at low temperatures leads to formation of adsorbed species of H2S as fragments HS- and S2-, which upon heating 100-700degreesC transfer into different species of sulfur: c-S-8, c-S-12, S-4. In separate experiments it was demonstrated that the higher the temperature of H2S interaction with Al2O3, the larger number of adsorbed sulfur species are observed in the spectra. Molecular hydrogen sulfide interacts with the Al2O3 surface with formation compounds of sulfur with oxygen, which later transform into the final reaction product - elemental sulfur. (C) 2002 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.