Preparation of NiW/TiO2-Al2O3 hydrodesulfurization catalyst with microwave technique

NiW/TiO2-Al2O3 catalyst samples were prepared by conventional drying method (CON-Cat) and by microwave irradiation method (MW-Cat and MW-Cat1). The HDS reactivity of thiophene over them was studied in a fixed-bed microreactor. The thiophene conversion over MW-Cat increased from 70.9% at 16 hr to 71.8% at 19 hr, while the thiophene conversion over MW-Cat1 kept to 71% after 17 hr and then increased very slowly. The HDS reactivity over CON-Cat increased slowly after 15 hr and the thiophene conversion increased from 63.3% at 15 hr to 69.4% at 19 hr. The activity difference between CON-Cat and MW-Cat was due to the different sulfidation performance. MW-Cat or MW-Cat1 could be sulfided to some extent by using shorter time than CON-Cat. The surface acidic properties of MW-Cat and MW-Cat1 were changed with microwave irradiation power and time. The amounts of weak and medium acid sites in MW-Cat and MW-Cat1 increased, while that of strong acid sites decreased. The strength order of weak and medium acids was MW-Cat < MW-Cat1 < CON-Cat. MW-Cat and MW-Cat1 were favorable for their sulfurization and had higher activity than CON-Cat.