Influence of different alumina phases on the catalytic properties of palladium-alumina catalysts for selective hydrogenation of acetylene to ethylene

Selective hydrogenation of acetylene was studied using palladium catalysts supported on different transition alumina spheres. The alumina supports were prepared by calcining pseudo boehmite alumina sphere at different calcination temperatures; the ρ-Al 2 O 3 used was flash calcined alumina. The alumina supports were characterized using different techniques like XRD, surface area, pore volume and acidity. The Pd/Al 2 O 3 catalyst were prepared, palladium penetration depth was measured using microscopic imaging and the catalyst reducibility were studied by Temperature Programmed Reduction (TPR). The microscopic imaging using TEM were done to study the palladium particle size and nature of particle clusters on the support surface. The catalyst performance evaluation was done in a fixed bed reactor with 1% acetylene in nitrogen feed and studied the impact of support properties on the catalytic activity. The catalyst prepared on γ-Al 2 O 3 support showed the highest conversion and lowest selectivity, whereas the catalyst on α-Al 2 O 3 support has the lower conversion and highest selectivity. Thermogravimetric analysis coupled with mass spectroscopy analysis were done for the spent catalyst to understand the possibilities of heavy component deposition of the catalyst. The catalyst prepared on α-Al 2 O 3 support had the lowest hydrocarbon deposit on the surface whereas the γ and δ alumina showed the highest hydrocarbon deposits on the catalyst surface.