Synthesis, Characterization And Hydroprocessing Performance Of Supported Tungsten Phosphide Catalysts

With the rapid development of world economy, the demand of each domain for oil is increasing year by year, the quality of fuel, especially the standard of sulphur content is becoming more strict to every country in the world. In the situation of which the traditional hydrodesulfurization technology already can’t meet the requirement of the fuel quality, the best breakthrough of realizing deep and ultra deep desulfurization is pinned on researching and developing the improvement of HDS catalyst. Because of the HDS activity, high mechanical strength, heat stability and special crystal texture and sulfur poisoning resistance in particular of the transition metal phosphide catalysts WP, it has been widely focused by the researchers at home and abroad.This paper uses temperature programmed reduction(TPR) method to prepare WP/γ-Al2O3 catalyst, and uses two benzothiophene cyclohexane solution for the model compounds, investigates the preparation condition, in situ reduction condition and reaction process condition of catalysts to the influence of catalyst’s HDS performance. Meanwhile research the impact of joining auxiliaries to the WP/γ-Al2O3 catalyst’s performance.The results shows that the best preparation condition of WP/γ-Al2O3 catalyst precursor will be appeared when active component is n(W):n(P)=1:1.1, capacity is 30 percentages, calcination temperature is 500℃, calcination time is 4 hours. The in situ reduction condition needs the reaction temperature be 400℃, reaction pressure be 3MPa, space velocity be 3h-1, the ratio between hydrogen and oil be 300.Adding the right amount of auxiliaries such as Ni、Co、Ce、La can improve the HDS activity of WP/γ-Al2O3 catalyst. According to the characterization analysis, we find that La auxiliary can make the grain size of WP/γ-Al2O3 catalyst become smaller, active component dispersion become better, the interaction between carrier and active component will be improved, the generation of active phrase become easier, thermal stability will be increase, the acidity of catalyst will be also increase. Introducing 3% dosage of La auxiliary can get the best effect, at this time the HDS percent conversion of La(3)-WP/γ-Al2O3 catalyst can reach to 87.63% which increase by 13.66% compared with La(3)-WP/γ-Al2O3 catalyst with no auxiliary.