关键词: ZSM-5, 改性, 酸性, 芳构化, 反应条件

Abstract: The influences of Zn, Pt and Re contents on the acidity and aromatization performance of Zn-Pt-Re/ZSM-5 catalyst were studied. The effect of reaction conditions, such as reaction temperature, pressure and volume space velocity (LHSV) on the performance of Zn-Pt-Re/ZSM-5 catalyst was investigated in a continuous flow micro-reactor using n-hexane as probe molecule. Test results showed that with the increase of Zn content in catalyst, the amount of Br?nsted (B) acid sites increased and Lewis (L) acid sites decreased gradually. The existence of Pt and Re (esp. Re) in catalyst was beneficial for increasing the amount of B acid sites. It was found that the alkane aromatization was the synergetic effect of B acid and L acid, and the aromatics yield could be enhanced when B/L ratio was about 0.2. There was a very good corresponding relationship between aromatics yield and the changing trend of medium-strong acid amount of catalyst. High reaction temperature was favored to aromatization reactions, an aromatics yield of over 95% could be obtained when the reaction temperature was over 450 ℃. However, high reaction pressure and high LHSV had negative effect on the conversion and aromatics yield. The optimum reaction conditions for aromatization of n-hexane over Zn-Pt-Re/ZSM-5 catalyst were obtained as follows：a reaction temperature of 450 ℃，a reaction pressure of 1.0 MPa and LHSV of 1.0 h-1.

Key words: ZSM-5, modification, acidity, aromatization, reaction condition