Preparation, Physiochemical and Kinetic Investigations of V2O5/SiO2 Catalyst for the Sulfuric Acid Production

Abstract

V2O5/SiO2 catalyst was utilized to oxidize SO2 to SO3 species in the presence of oxygen mainly for producing sulfuric acid. For this catalyst, the active phase was a mixture of vanadium pentoxide and basic sulfate/pyrosulfate material. This active phase at the reaction temperature behaved as a liquid filling up the pores of the silica support. On the other hand, amounts of the SO3 and V5+ species in the catalyst necessarily varied with the concentration of the feed material and temperature rendering complexity to the kinetics of the SO2 oxidation reaction. In the current research, the catalyst preparation with different amounts of such materials was undertaken. Purified diatomaceous earth of a Persian Gulf beach was chosen as the support for this catalyst. The suitability of the prepared catalyst to determine the reaction kinetics was confirmed through the XRD, XRF and BET-BJH analyses as well as color analysis. Moreover, the aforementioned reaction kinetics was studied empirically. In addition, a model for the reaction rate using the response surface methodology (RSM) was presented. In this venue, factors including the reaction temperature as well as conversion were considered. This reaction kinetics determined at the operating conditions of 380-420 °C, 0.108 MPa and feed gas composition of 10 wt.% SO2, 18.9 wt.% O2 and 71.1 wt.% N2. It was revealed that, obtained kinetic rate constants satisfied the Arrhenius relationship from which the activation energies were determined.