Oligomerization of Ethylene in Fluidized Catalytic Cracking (FCC) Dry Gas to Propylene

Abstract

Oligomerization of ethylene in fluidized catalytic cracking (FCC) dry gas to propylene was investigated as a feasible approach to use FCC dry gas. The thermodynamic calculation indicated that the equilibrium conversion of ethylene decreased with an increasing temperature, while the experimental conversion achieved peak value at nearly 500°C due to kinetic limit. The catalytic performances of HZSM-5 catalysts with FCC dry gas as feedstock were studied in fixed-bed reactor. It was confirmed that oligomerization carried out at a higher temperature using dilute feed or a less active catalyst such as steam treated catalyst favored propylene yield. With ethylene conversion of approximately 50%, the propylene yield was over14% at 0.3MPa, 550°C with dilute ratio of 1:1 over steam treated catalyst. An apparent reaction order of 2.5 with respect to ethylene was obtained.