Abstract
This study is aimed to understand the role of alkaline earth elements (AEE) to the catalytic performance of PtSnM1/gamma-Al2O3 catalyst for the direct propane dehydrogenation (where M-1 = Mg, Ca, Sr, Ba). All the catalysts were prepared by using wet impregnation. The overall catalytic performance of all the catalysts was studied at different reaction temperatures, feed composition ratios and GHSV. The best operating reaction conditions were 575 degrees C, feed composition ratio of C3H8:H-2:N-2 = 1.0:0.5:5.5 and GHSV of 3800h(-1). An optimal addition of "Ca" to PtSn//gamma-Al2O3 catalyst, enhanced the catalytic activity of PtSnM1/gamma-Al2O3 catalyst in comparison to other studied AEE. This catalyst had shown the highest propane conversion (similar to 55.8 %) with 95.7 % propylene selectivity and least coke formation (7.11 mg.g(-1)h(-1)). In general, the increased catalytic activity of PtSnM1/gamma-Al2O3 is attributed to the reduced coking extent during the reaction. In addition, the enhanced thermal stability of the PtSnCa/gamma-Al2O3 catalyst is because of the protective layer between gamma-Al2O3 and active metal, which allows the formation of active species such as PtSn, PtCa2 and Pt2Al phases?