关键词: 溶胶凝胶法, Mo-Ni复合氧化物, 加氢脱硫, 二苯并噻吩

Abstract:

The bulk Mo-Ni composite oxide catalysts were prepared by sol-gel method and were characterized by XRD、BET、NH3-TPD. Using 2 wt% DBT- n-octane solution as the feed, the HDS performance of the catalysts were tested in a continuous flow fixed-bed reactor. According to the results of characterization and evaluation, the effects of calcination temperature, the solution pH of sol-gel process and the addition of starch on the properties and catalytic performance of the catalysts were investigated. The characterization results showed that oxided catalysts under more than 500℃ calcination were mainly composed of crystalline phase α-NiMoO4 and β-NiMoO4, while the sulfided catalysts were mainly composed of MoS2 and Ni2S3. The increasing of calcination temperature is beneficial for the formation of α-NiMoO4, while the enhancement of the alkaline solution is favorable to the formation of β-NiMoO4, the both significantly reduce the total acidity of catalysts. The addition of starch has little fact on the crystalline phase of oxided catalyst, but it can improve the dispersion of active component. The introduction of appropriate amount of starch can increase the specific surface area and pore volume of the catalysts. The results of hydrodesulfurization reaction indicated that the catalyst prepared under the conditions of calcination temperature 600 ℃, the pH solution 2, the starch amount 15g/(Mo+Ni)mol, exhibited a higher hydrodesulfurization activity. Under the conditions of 260 ℃, 2 h-1, 2.5 MPa and H2/oil volume ratio 300, the desulfurization rate of the feed containing 3 480 μg/g S over the catalyst reached to 98.3%, hydrogenation desulfurization (HYD) pathway was the prior way during the HDS reaction of DBT, and the HYD/DDS( direct desulfurization) ratio was 1.23.

Key words: sol-gel method, Mo-Ni bulk catalyst, HDS, DBT