(97a) Reactor Scale Modeling of Liquid Phase Ethylene Production By Hydrogenation of Acetylene in a Trickle Bed Reactor

Selective hydrogenation of acetylene to ethylene from the cracker effluent using Pd-based catalyst has been studied extensively due to the catalyst deactivating nature of acetylene. It acts as a catalytic poison to the polymerization catalyst used in the production of polyethylene and other valuable products from ethylene. Gas phase hydrogenation of acetylene to ethylene has been widely employed in many industries to reduce the acetylene content less than 5ppm. Liquid phase hydrogenation of acetylene is of recent interest as this process can not only avoid runaway conditions which may occur while using a gas phase but also minimize the formation of green oil. A modified reactor scale model was developed to understand and simulate the liquid phase selective hydrogenation of acetylene. A one-dimensional mathematical plug flow model was combined with a particle scale model accounting for the partial wetting of the catalyst. A sequential approach is proposed to evaluate the variables in the plug flow and particle scale model. The reactor scale model identified the local concentration along the reactor axis while the local effectiveness factor was obtained from the particle scale model for the corresponding local concentration. An algorithm was written to calculate the effluent concentration, reaction rate, and conversion in the flow direction. The model was simulated with a set of operating conditions adapted from literature. The performance of fixed-bed reactors in both trickle and upflow will be compared using appropriate correlations.