Development and Industrialization of the Ethylbenzene Production Technologies from Dilute Ethylene in FCC Dry Gas

Abstract

This article demonstrates the design and industrial operation results of the ethylbenzene(EB) production technology from FCC dry gas by a combination of gas-phase alkylation and liquid-phase transalkylation, developed and commercialized by Dalian Institute of Chemical Physics (DICP), CAS. Based on the high active modified ZSM-5/ZSM-11 co-crystalline zeolite alkylation catalyst and modified β zeolite transalkylation catalyst, both the alkylation and transalkylation reactions are performed under much milder conditions, resulting in low energy cost and low content of xylenes impurities in the EB product. Also, the novel process for EB production, developed by DICP recently, through alkylation of dilute ethylene with gas-liquid mixed phase benzene and transalkylation feed is optimized. The results show that the transalkylation feed addition into the middle-lower part of the reactor improves the EB selectivity from about 90% to more than 99%, and the alkylation and transalkylation reactions are unified into a single reactor. Moreover, the alkylation reaction temperature decreases from more than 320 °C to about 170 °C, and the content of the xylenes impurities in the EB product is further decreased to less than 100 ppm.