The simulated countercurrent moving bed chromatographic reactor: a novel reactor—separator

Abstract

The simulated countercurrent moving bed chromatographic reactor (SCMCR) is a device for carrying out chemical reaction and separation simultaneously in a fixed bed. This is a novel reactor type in which separation takes place at the site of chemical reaction to improve product purities and conversions beyond those prescribed by thermodynamic equilibrium. The simulated countercurrent system mimics the behavior of a countercurrent moving bed by periodically changing feed and product locations sequentially along a fixed bed. The present investigations endeavor to determine to what extent the moving bed reactor advantages of high product purity and favorable equilibrium shifts are retained in SCMCR operations. An equilibrium stage model of the SCMCR consisting of a single fixed bed having series of inlets and outlets along its length is considered. The mass balance equations are discretized to give an equilibrium plate model. Predictions of the concentration profiles in the column(s) are obtained for the 1,3,5-trimethylbenzene hydrogenation reaction at 463 K. It is shown that reaction and separation can be achieved simultaneously and that the yield of the reversible reaction can be improved greatly. Under appropriate operating conditions, the model calculations predict high-purity product streams and nearly complete conversion of a reaction which would otherwise be limited by equilibrium to 62%.