Abstract: The effect of Pt loading method, the pH of precursor solution and the Pt loading amount on hydroisomerization of Pt/ZSM-22-γ-Al2O3 was investigated for hydrocracking tail oil. The results show that the catalyst prepared by ion-exchange after support forming has the highest dispersion of Pt. The hydroisomerization selectivity and activity order is: ion-exchange after forming > molecular sieve ion-exchange > impregnation. When the pH of precursor solution of ion-exchange after forming is 9 and the Pt loading is 0.30%, the dispersion degree of Pt is 87.2%, the yield of 150N base oil with a pour point of -15℃ is 75.8%, and the hydroisomerization selectivity achieves the best.

Key words: ion exchange, molecular sieve, impregnation, Pt loading, pH