Effect of addition different promoters to Pt-Sn-K /Al2O3 catalyst in the propane dehydrogenation

The effect of addition different promoters, La, Ir, Re and Cs to trimetallic Pt-Sn-K/Al2O3 catalyst on its performance in propane dehydrogenation was studied. The trimetallic Pt/Sn/K and tetramettalic catalysts Pt/La/Sn/K, Pt/Ir/Sn/K, Pt/Re/Sn/K and Pt/Sn/Cs/K were prepared by sequential impregnation of γ-alumina support. The catalysts were characterized by TPD and TPR tests. Catalytic performance test were carried out in a fixed-bed quartz reactor for propane dehydrogenation activity and propylene selectivity under representative industrial conditions. The Pt/Sn/Cs/K catalyst showed better performances in terms of propylene selectivity. The performance of Pt/Sn/Cs/K catalysts was further improved by adjusting Cs loading to the trimetallic (Pt/Sn/K) catalyst. The addition of Cs to Pt-Sn-K/Al2O3 catalyst improved catalytic performance through modifying the nature of acidic function of the support. It was also found that the toxicity of the alkali metals on the acid character of alumina increases with the ionic radius.

Keywords:

Propane dehydrogenation , Pt-Sn catalysts , promoter , catalyst performance