Abstract: In response to the high benzene content in FCC (fluid catalytic cracking) gasoline, this study employed a TZ catalyst with ZSM-5 zeolite as the active component to investigate the effects of reaction temperature and space velocity on the alkylation reaction of gasoline and ethylene in a fixed-bed reactor. The influence of reaction pathways on product distribution and aromatic composition was also analyzed. The results indicated that when ethylene was fed alone, reactions such as oligomerization, cracking, and cyclization-dehydrogenation primarily generated propane and aromatics, with benzene accounting for 10% of the total aromatics. When gasoline was fed alone, olefin hydrogen transfer reactions dominated, accompanied by cracking and condensation reactions. For the mixed system of gasoline and ethylene, the alkylation reaction between benzene in gasoline and ethylene exhibited optimal performance at 330 °C, achieving nearly complete ethylene conversion, high gasoline yield, and a benzene removal rate of 36.69%. However, at 360 °C, side reactions such as cracking and cyclization-dehydrogenation intensified, leading to an increase in benzene content. Under low mass space velocity conditions (1.2-2.0 h^-1), ethylene was nearly completely converted, whereas at a mass space velocity of 3.0 h-1, the reduced residence time inhibited ethylene conversion.

Key words: FCC gasoline, ethylene, benzene content, alkylation, reaction pathway