Oxidative Decomposition of H2S over Alumina-Based Catalyst.

An Al2O3-based catalyst was employed for the first time in the H2S oxidative decomposition in order to obtain simultaneous sulfur and hydrogen. The influence of the reaction temperature (in the range of 700-1100 °C) and the contact time (in the range of 17-33 ms) were investigated in terms of H2S conversion, H2 yield, and SO2 selectivity. Good catalytic performances were obtained at 1000 and 1100 °C with experimental values very close to those ones expected from the thermodynamic equilibrium. At a temperature of 1000 °C, the H2S conversion and H2 yield were, respectively, about 50% and 17%; in particular, the SO2 selectivity decreased of a magnitude order ~0.5% with respect to the value observed in the homogeneous case (4%). A predictive mathematical model of H2S oxidative decomposition in the presence of a catalyst was developed through the identification of the main reactions occurring in the system. The results obtained from the kinetic investigations evidenced that the catalyst, in addition to the H2S decomposition reaction and the partial oxidation reaction to sulfur, was able also to promote the SO2 conversion by the Claus reaction allowing it to avoid the presence of SO2 at the reactor outlet. [ABSTRACT FROM AUTHOR]