Catalytic Performance Of Metal/TiO₂ -SAPO-11 Catalyst For N-heptane Isomerization

With the strengthening of the environmental protection, the requirement of clean gasoline, diesel and advanced lubricant products increased. Therefore, the technique of n-alkanes hydroisomerization for the production of high quality petroleum products received more and more attention. Among the n-alkanes hydroisomerizations, n-heptane hydroisomerization was of vital significance to improve the front-end octane rating of the gasoline and the viscosity-temperature of the diesel.In this paper, SAPO-11 molecular sieve was prepared by hydrothermal crystallization method, and TiO₂-SAPO-11 was prepared by the sol-gel method. Ni/TiO₂-SAPO-11 and Co/TiO₂-SAPO-11 catalysts were synthesized. The catalytic activities of Ni/TiO₂-SAPO-11 and Co/TiO₂-SAPO-11 for n-heptane hydroisomerization were investigated. Catalyst preparation conditions, reduction conditions and reaction conditions were discussed elaborately.Results showed that when nickel loading was 2%, reduction temperature was 500 oC, reduction time was four hours with the hydrogen velocity of 30 mL/min, and the reaction temperature was 320 oC, the conversion of n-heptane and the isomerization selectivity reached 40.94% and 88.97%, respectively, for Ni/TiO₂-SAPO-11.While for Co/TiO₂-SAPO-11 catalyst, when cobalt loading was 3%, reduction temperature was 500 oC, reduction time was five hours with the hydrogen velocity of 30 mL/min, and the reaction temperature was 300 oC, the conversion of n-heptane and the isomerization selectivity reached 13.67% and 92.34%, respectively.