Reduction of benzene in reformate by ethylene alkylation with benzene

Abstract

Benzene is a key aromatic hydrocarbon which is an important high octane component of motor gasoline; however, benzene is known as a human carcinogen and also has high vapor pressure thus high evaporative emissions. Reformate is the largest portion of benzene in a gasoline pool and, therefore it was aimed to reduce benzene content prior to blending. Alkylation of reformate with ethylene was investigated in this research work. The reaction was performed in an autoclave reactor with a temperature of 225 °C and pressure of 45 bar for 20 h using β- zeolite as a catalyst. The alkylation products showed the increasing in research octane number (RON) and distillation temperature with decreasing in blending Reid vapor pressure (bRvp) because ethylbenzene is produced instead of benzene. Thus the process improves gasoline quality in both term of technical and environmental viewpoint. Benzene conversion is higher with higher ethylene in feed. Moreover, modified β-zeolite with Ga further improved benzene conversion and RON with decreasing bRvp. However, this improvement with Ga modification might not because of the enhancement of alkylation between benzene and ethylene as proven by the probe reaction of pure benzene with ethylene.