The Effect of Hydrothermal Treatment on the Aromatization Performance of HZSM-5 Modified by Zn, P

Abstract

Zn and P modified HZSM-5 zeolite catalysts were prepared by impregnation method using HZSM-5 zeolite prior to hydrothermal treatment. The surface area, the acid center style, and the acid strong distributing on hydrothermal treatment HZSM-5 zeolite were characterized by XRD, BET, NH3-TPD, and FT-IR techniques. Meanwhile, the influence of hydrothermal treatment temperature on the aromatization performance of the catalyst was investigated using FCC gasoline (50–100°C fraction) as feedstock. The result showed that, along with the temperature of hydrothermal treatment heightening, the surface area reduced and pore volume increased a little, however, the pore size clearly increased; at the same time the total acid amount and the number of strong acid sites of HZSM-5 were reduced significantly. With the hydrothermal treatment temperature increasing, the catalyst initial activity gradually decreased and the stability presented the trend of first increase then decrease. The HZSM-5, which was treated by hydrothermal at 550°C modified by zinc and phosphor, exhibited preferable aromatization performance. After reacting 16 h, the conversion of olefins, the contents of aromatic, and the yield of liquid products were 90.26, 54.06, and 10.02%, respectively.