Cumene from Benzene and RG Propylene (Zeolite Catalyst)

The process under analysis comprises two major sections: (1) Reaction; and (2) Distillation.

Reaction. In the reaction section, there are two reactors - the alkylation reactor and the transalkylation reactor. Fresh refinery grade propylene and recycled benzene are mixed and fed to the alkylation reactor. The alkylation reactor effluent comprises in addition to the Cumene product, unreacted benzene, non-reactive propane (present in the propylene feed), side products polyisopropylebenzenes (PIPB) and heavy ends. The effluent is routed to the Depropanizer column in the distillation section. The transalkylation reactor, in turn, is fed with recycled benzene and PIPB recovered in the distillation section. In the transalkyation reaction, PIPBs are reacted with benzene to form Cumene. The transalkylation reactor effluent is routed to the Benzene Recovery column in the distillation section.

Distillation. In the distillation section, a depropanizer column removes non-reactive propane from the alkylation reactor effluent. The propane-free reaction effluent is routed to the Benzene Recovery column, while propane is purged from the process. The Benzene recovery column is also fed with fresh benzene and the product of the Transalkylation reactor. Benzene is separated and recycled to the reaction section, while a crude Cumene stream obtained from the bottom of the column is routed to the Cumene purification column, from which high-purity product is obtained. The impurities rejected in the Cumene column are treated in a further column, which recovers PIPB for the transalkylation reaction.