Abstract: Both the influence of quinoline on hydrodesulfurization (HDS) of dibenzothiophene (DBT) and the effect of DBT on hydrodenitrogenation (HDN) of quinoline were studied over a presulfided NiMoS/γ-Al2O3catalyst in a fixed-bed high pressure microreactor. The results suggested that quinoline could strongly inhibit the HDS reaction of DBT, where the inhibitory effect on the hydrogenation route (HYD) was stronger than that on the direct desulfurization route (DDS), which resulted from the competitive adsorption of quinoline and intermediate products of HDN reaction on active sites. The different inhibitory extent of quinoline on the DDS route at 300 and 340 ℃ was closely related to the relative amount of HDN intermediate products. DBT had a positive influence on hydrodenitrogenation ability, which was due to H2S released in the HDS reaction. H2S promoted the conversion of coordinatively unsaturated sites to Brnsted acid sites on the catalyst surface, which in turn facilitatedC(sp3)-Nbond cleavage of the HDN intermediate molecules. Although the formation of active sites for HDN must be in the presence of S, the maintenance of active sites does not need too much S.

Key words: nickel, molybdenum, sulfur, alumina, dibenzothiophene, hydrodesulfurization, quinoline, hydrodenitrogenation, mutual influence