Effect of Indole on Hydrodesulfurization Performance of NiMo/γ-Al2O3 Catalyst in a Slurry System
浆态体系中吲哚对NiMo/γ-Al2O3加氢脱硫性能的影响

Hydrodesulfurization (HDS) performance of the presulfurized hydrogenation catalyst NiMo/γ-Al2O3 was studied using dibenzothiophene (DBT) as model compound with and without addition of 1000 mg/L indole (based on N) under 300℃ and 4.5 MPa. Sulfur content and species concentration were measured using micro-coulometric analyzer and gas chromatography-mass spectrometry, respectively. The fresh and used catalysts were characterized by BET, XRD, TEM, TPD and TGA. The results showed that the addition of indole slightly increased the reaction rate in the activation period, but significantly decreased the rate in the subsequent stable reaction period, leading to an overall decrease in desulfurization rate from 70% to 58%. The used catalyst did not change in surface topography and crystalline structure compared with the fresh catalyst, but showed an increase in specific surface area. The addition of indole caused 12% decrease in the catalyst pore size and 50% increase in coke formation, and significantly deceased the production of cyclohexyl benzene, indicating that the hydrogenation desulphurization route was suppressed.