Effect of impregnation methods on nickel-tungsten catalysts and its performance on hydrocracking Fischer-Tropsch wax

Three hydrocracking catalysts were prepared by impregnation method with different incorporation manners of Ni/W metals on HY/Al₂O₃ support. The effect of combination methods on acidity, hydrogenation capability of the catalysts and its hydrocracking performance on FT wax was studied. The balance between hydrogenation performance and cracking performance could be modulated by adjusting the metal-support combination methods. Ni/W pre-impregnated on HY can increase the hydrogenation capability of the catalyst and simultaneously lower the acidity of the support. The results show that the coordination of high hydrogenation capability and low acidity of catalyst can inhibit the formation of secondary cracking on some extent, and increase the selectivity of diesel. While Ni/W metals supported on HY/Al₂O₃ can achieve a relative balance of hydrogenation and cracking, thus the catalysts have a higher activity and the more flexible ability to modulate reaction.