The Preparation Of Supported Catalyst With Re And Its Application In Oil Hydrofining

With the improvement of environmental protection awareness of the public and the increasingly strict environment regulations, developing new effective hydrodesulfurization, hydrodenitrogenation and hydrodearomatization catalyst become a hotspot in the field of hydrofining.Conventional CoMO/Al2O3 or NiMo/Al2O3 hydrotreating catalysts are not sufficiently active for performing deep desulfurization hydrodenitrogenation and hydrodearomatization of diesel and gasoline under conventional operating conditions. To improve the activity of hydrotreating catalysts, one of the approaches is to develop new catalytic formulations with more active phases. Systematic studies on transition metal sulfides showed that rhenium sulfide exhibits high activity for hydrotreating reactions, generally higher than that of molybdenum or tungsten sulfides. Remarkably Re catalysts can have activities an order of magnitude greater than Mo ones. In agreement with such early findings, more recent studies have shown that alumina supported ReS2 alone exhibits high activity for hydrodesulfurization, hydrodearomatization and especially hydrodenitrogenation of a gas oil feedstock, and also that ReS2/Al2O3 catalysts can display higher activity than a commercial CoMO/AI2O3 or NiMo/Al2O3 catalyst in the HDS of thiophene.Ternary composite oxide of SiO2-TiO2-ZrO2 was prepared by coprecipitation method, The catalysts were characterized using X-ray diffraction, nitrogen absorption. The specific surface area (SBET)of the support were determined from analysis of nitrogen adsorption, The specific surface area, pore volume and pore size measured are 265.80 m2·g-1,0.33 cm3-g-1,6.86nm, respectively.It is typical mesoporous materials with large specific surface. The specific surface area, pore volume and pore size of ernary composite oxide of SiO2-TiO2-ZrO2 are higher than binary composite oxide support. From XRD spectrogram we obtain that TiO2 anatase of support forms sharp peak.Two series of WReNi/SiO2-TiO2-ZrO2 and WReCo/SiO2-TiO2-ZrO2 catalysts were prepared by co-impregnation of the supports with activity metal components loadings of 25wt%. The trimetallic catalysts were characterized by using X-ray diffraction (XRD), nitrogen absorption. The XRD patterns for catalyst show that after loanding activity metal components, the support main peak enhance, the diffraction peaks corresponding to activity metal components phase become weak, it is shown that activity metal components equably dispersed totally on the support; nitrogen absorption indicate that after loading activity metal components the specific surface area, pore volume and pore size for support become small, it show that activity metal components are inserted into the structure of support.The catalyst with varying activity metal components ratios were evaluated under the same reaction temperature, LHSV, H2/gas oil ratio, and various pressure. The catalytic performance of desulfurization, hydrodenitrogenation and hydrodearomatization was evaluated in a high-pressure micro flow reactor using Thiophene, quinoline, tetrahydronaphthalene as model compound, and ordinary pure hydrogen as reducing gas. The result shown that the desulfurization conversion rate increases with the increase of reaction pressure; HDS activity was significantly higher than HDN and HDA activity. The HDN reaction have greater activity, the conversion rate of quinoline. the conversion rate of quinoline have a maximum at 3.5 MPa. The HDA activity of catalyst is lowest, gradually increase with the increase of reaction pressure, it indicated that pressure on the catalyst HDA effect is obvious.Experiment selected reaction pressure, reaction temperature, LHSV, oil-hydrogen ratio for the factors of orthogonal test. The HDS, HDN and HDA of catalyst proceed the evaluation of activity, obtained the favorable conditions of the HDS, HDN and HDA were gotten through an orthogonal test.