The liquid phase hydrogenation of benzene and substituted alkylbenzenes over a nickel catalyst in a semi-batch reactor

Abstract

The liquid phase hydrogenation kinetics of benzene, toluene, ethylbenzene and cumene was studied in a three-phase semibatch reactor at pressures of 20–40 bar and at temperatures of 95–140°C. The experimental kinetics was described with a rate equation based on rapid adsorption and desorption steps and slow consecutive hydrogen steps. A pseudo-homogeneous model neglecting the diffusion resistances in the catalyst particles was able to phenomenologically describe the observed kinetics, but numerical simulations showed that there exist significant concentration gradients in the particles. Therefore a complete dynamic heterogeneous model was developed for the reactor and the catalyst particles including the reaction-diffusion process. The kinetic parameters were re-determined using the heterogeneous reactiondiffusion model. The model enables the investigation of the reaction-diffusion effects and the dynamics of the catalyst particles.