Study of MoO-γAlO catalysts behavior in selective catalytic reduction of SO toxic gas to sulfur with CH.

In the present study, a detailed investigation was carried out on MoO alumina-supported catalysts behavior in selective catalytic reduction of SO to sulfur with CH. At first, four different molybdenum catalysts with weight rates of 0, 5, 10, and 15 were impregnated on γ-alumina to be characterized using XRD, SEM, BET, BJH, and N adsorption. Then, to find the most active catalyst, temperature dependency test was performed on all of the prepared catalysts and the result representing Al2O3-Mo10 as the best catalyst. In next step, the effects of feed gas composition, space velocity, and long-term activity, as an important industrial factor, were tested on AlO-Mo10. It was revealed instantaneously from the beginning, MoO specie started to convert mainly into MoS and MoO, and a minor part into MoC, which is terminated after 750 min achieving a stable condition. Thereafter, SO conversion and sulfur selectivity increased from 85.8 to 89.4% and 99.4 to 99.7%, respectively. XRD graph of the used catalyst and TPO thermogravimetric/mass-spectra proved possible happening of the proposed mechanism in long-term activity. At the end, mean activation energy was determined based on Arrhenius model in temperature range of 550 to 800 °C, with a value of 0.33 eV for AlO-Mo10.