Design and Control of the Cumene Process

Abstract

The chemistry of the cumene process features the desired reaction of benzene with propylene to form cumene and the undesirable reaction of cumene with propylene to form p-diisopropylbenzene. Both reactions are irreversible. Since the second has a higher activation energy than the first, low reactor temperatures improve selectivity of cumene. However, low reactor temperatures result in low conversion of propylene for a given reactor size or require a large reactor for a given conversion. In addition, selectivity can be improved by using an excess of benzene to keep cumene and propylene concentrations low, but this increases separation costs. Therefore, the process provides an interesting example of plantwide economic design optimization in which there are many classical engineering trade-offs: reactor size versus temperature, selectivity versus recycle flow rate, and reactor size versus recycle flow rate. Design optimization variables affect both energy costs and capital investment. They also affect the am...