Ni-W/Si-MCM-41加氢脱硫催化剂中Ni的助剂作用

在中压固定床反应器上，以含质量分数0．2％～0．8％二苯并噻吩（DBT）的十氢萘溶液为模型化合物，考察了Ni—W／Si—MCM-41催化下的加氢脱硫反应（HDS）动力学。结果表明，HDS反应的表观活化能（EHDS）和氢解反应的表观活化能（EHYG）在Ni／W摩尔比为0．75时最小，而加氢反应的表观活化能（EHYD）则随Ni／W摩尔比的增加单调降低，表明在Ni—W／Si—MCM-41催化剂上加氢和氢解的活性中心不同。紫外／可见漫反射光谱（UV—Vis）和程序升温还原技术（TPR）表征的结果表明，Ni—W／Si—MCM-41的加氢活性中心可能与催化剂表面八面体配位的Ni物种有关，而氢解活性则与NiO-WO3混合物种的还原性能有一定对应关系。

ROLE OF Ni IN Ni-W/Si-MCM-41 HYDRODESULFURIZATION CATALYSTS

The kinetics of hydrodesulfrization (HDS) of dibenzothiophene (DBT) catalyzed by Ni-W/Si-MCM-41 was studied by using a model mixture containing 0.2%-0.8%(mass fraction) DBT in decalin. The results indicated that Ni-W/Si-MCM-41 with the Ni/W molar ratio of 0.75 exhibited the lowest HDS apparent activation energy (E_(HDS)) and hydrogenolysis apparent activation energy (E_(HYG)), whereas the apparent activation energy of hydrogenation reaction (E_(HYD)) decreased with the increase of the Ni/W molar ratio, which suggested that the two reactions take place on different types of catalytic sites. It was further confirmed by the results of UV-Vis and TPR that the active site of hydrogenation was correlated with the octahedrally coordinated Ni species, while the hydrogenolysis activity of Ni-W was related with the reducibility of NiO-WO_3 species.