Light alkanes dehydrogenation over silica supported gallium catalysts

Abstract

The present work is devoted to the studies of Ga/Silica catalysts in the paraffins dehydrogenation of natural gas - propane and ethane to produce valuable products - olefins and hydrogen. The gallium oxide supported on silica gel (2–10 %wt. of Ga) have been studied using XRD, TPR-H₂ and STEM/EDS methods, it has been shown that the dispersion of gallium oxide over the silica surface is very effective, the support actively reacts with a gallium salt to form surface particles that are more easily reduced than pure gallium oxide. Under steady and no-stationary state the negative effect of oxidative pre-treatment and the addition of CO₂ to the reaction mixture on catalytic activity was detected. On the contrary, pre-treatment of the catalysts in hydrogen (at 650–700 °C) or CO addition to the reaction mixture was accompanied by an increase in their propane dehydrogenation activities and stabilities at 600 °C. In the ethane dehydrogenation conditions (650 to 700 °C) catalysts is effective treated by hydrogen during the experiment. At 700 °C, the Ga/Silica activity may even increase during ethane dehydrogenation. By TPR-H₂ it was observed that with an increase in the temperature of pre-treatment of Ga/Silica in hydrogen from 650 to 700 °C, the proportion of oxidized Ga-containing phase significantly decreases.