Computer-Aided Design for a Demonstration-Scale Packed-Bed Tubular Reactor Producing Epichlorohydrin

Abstract

Temperature control is crucial when designing a catalytic tubular reactor for an exothermic reaction because hot spots in a packed-bed tubular reactor affect conversion, selectivity and lifespan of solid catalysts (Fogler, 1999; Bartholomew, 2001; Singh et al., 2008). In order to resolve the hot spot problems in scale-up of a packed-bed tubular reactor, a computer-aided design method combining a process modeling software package, heat exchanger design software and computational fluid dynamics (CFD) analysis is proposed. The proposed design method is composed of three steps as follows: Firstly, the length and the number of packedbed tubes are determined to achieve a target production rate by the simulation results of the pilot-scale reactor model. Secondly, the detailed geometry of the scaled-up reactor comprising multiple tubes is determined using commercial heat exchanger design software. Finally, optimal operating conditions are designated to control the hot spot in the reactor tubes based on the CFD studies. The design method is applied to the scale-up of the previously developed pilot-scale reactor, where epichlorohydrin (ECH) is produced and the production rate is approximately 0.54 kg/h, so that a demonstration-scale multi-tube reactor producing 100 kg ECH/h is designed and the optimal operating conditions of the reactor are also determined.