Hierarchically porous Beta/SBA-16 with different silica-alumina ratios and the hydrodesulfurization performances of DBT and 4,6-DMDBT

摘要

Hierarchically porous Beta/SBA-16(BS)composite materials,combining the characteristics of the acidity from the Beta zeolite and the three-dimensional structure from SBA-16,were synthesized successfully through a two-step in-situ assembly hydrothermal crystallization method.A series of Ni Mo catalysts supported on BS with different silica-alumina ratios were prepared.The supports and the corresponding catalysts were characterized by XRD,N_(2) physisorption,^(27)Al MAS NMR,TEM,pyridine-FTIR,Raman,XPS and HRTEM.The activities of series catalysts were evaluated by the hydrodesulfurization(HDS)performances of dibenzothiophene(DBT)and 4,6-dimethyldibenzothiophene(4,6-DMDBT).It was found that the Beta crystallites were embedded into SBA-16 through silanols accompanied by dealumination on the T3-T9 sites of Beta crystallites.Ni Mo/BS-3 with a silica-alumina ratio of 100 exhibited the highest DBT and 4,6-DMDBT HDS activities at the WHSV value of 10 h^(-1),with the conversions of 95.9%and 86.9%respectively,due to the synergistic effects of the suitable specific surface areas,the relatively large pore size,appropriate acidity,the relatively high sulfidation degree,moderate dispersity and good stacking degree of Mo S;active phases.