Alkylation of Benzene by Propylene to Cumene

Isopropylbenzene, also known as cumene, is among the top commodity chemicals, taking about 7 – 8% from the total worldwide propylene consumption. Today, the cumene is used almost exclusively for manufacturing phenol and acetone. This case study deals with the design and simulation of a medium size plant of 100 kton cumene per year. The goal is performing the design by two essentially different methods. The fi rst one is a classical approach, which handles the process synthesis and energy saving with distinct reaction and separation sections. In the second alternative a more innovative technology is applied based on reactive distillation. Table 6.1 presents the purity specifi cations. The target of design is achieving over 99.9% purity. It may be seen that higher alkylbenzenes impurities are undesired. Ethyl and butylbenzene can be prevented by avoiding olefi ns and butylenes in the propylene feed. N propylbenzene appears by equilibrium between isomers and can be controlled by catalyst selectivity. In this project we consider as raw materials benzene of high purity and propylene with only 10% propane. As an exercise, the reader can examine the impact of higher propane ratios on design.