助剂对WP/γ-Al_2O_3催化剂二苯并噻吩加氢脱硫活性的影响

DIBENZOTHIOPHENE HYDRODESULFURIZATION ACTIVITY OF SUPPORTED CATALYST WP/γ -Al_2O_3 PROMOTED BY DIFFERENT PROMOTERS

以γ-Al2O3为载体,以Ni、Co及P为助剂,采用程序升温还原法合成了不同助剂含量的负载型磷化钨催化剂,并对合成的催化剂进行了BET、XRD、NH3-TPD和TEM表征。以二苯并噻吩、环己烷为模型化合物,通过高压微反装置,对催化剂的加氢脱硫(HDS)活性进行了测定。结果表明,助剂Ni、Co对催化剂的表面酸性和活性组分分散有一定的影响,适量助剂Ni、Co和过量P的加入有利于提高负载型磷化钨催化剂的加氢脱硫活性,当镍或钴助剂质量分数为3%时,催化剂具有最佳的催化活性,在低温300℃和高温360℃时其二苯并噻吩脱硫率均在90%以上;在反应温度320℃时,过量5%的P比同样含量的助剂Ni或Co具有更好的助催化作用。低温有利于催化剂二苯并噻吩加氢脱硫,高温有利于噻吩加氢脱硫。

A series of alumina supported tungsten phosphide catalysts with nickel, cobalt and phosphor as promoter were prepared by temperature programmed reduction and characterized by BET surface area measurements, X-ray diffraction (XRD), ammonia temperature-programmed desorption (NH3-TPD) and TEM. The activities of the catalysts to hydrodesulfurization (HDS) were tested in a high pressure micro-reactor using a model liquid feed consisting of dibenzothiophene and cyclohexane. The results show that surface acid and activities of the catalysts were affected significantly by the nickel, cobalt promoter. Hydrode-sulfurization of WP/γ-Al2O3 catalysts was increased with proper nickel, cobalt and excess phosphor. When mass fraction of Ni or Co was 3%, WP/y-Al2O3 catalysts had the best activity, dibenzothiophene HDS conversions were all above 90% at the reaction temperature of 300°C and 360°C. The catalyst with 5 % excess phosphor had better HDS activity than others with the same content nickel or cobalt promoter at a reaction temperature of 320°C. It shows that higher dibenzothiophene HDS activities at lower reaction temperature, while higher thiophene HDS activities at higher reaction temperature.