Study Of Sulfided Hydrotreating Catalysts Preparation Process For Diesel

The production of clean diesel is not only the coerce of environmental protection,but alsothe inevitable requirement of the social sustainable development. The application ofhydrotreating in the removal of sulfur from diesel is one of the most efficient ways to produceclean diesel. However, it is the core technology in hydrogenation process that we shoulddevelop efficient hydrotreating catalyst, which is supposed to be. This paper covers thepreparation process of hydrotreating catalyst and try to develop an optimal and efficientpreparation technology of sulfided diesel hydrotreating catalyst.The experiments were carried out through low-temperature N2physical adsorption toinvestigate the nature of alumina support, which were prepared from the the WanLin and SBaluminium hydroxide powder with different proportions.The BET results showed that whenthe dry basis ratio of WanLin and SB powder was7:3, γ-Al2O3support had the appropriatepore structure properties and its specific surface area was300m2/g, which was appropriate fordiesel hydrotreating catalyst. Mechanical mixing the appropriate USY zeolite or acidic silicasol with alumina support respectively, the results indicated that support with the incorporationof USY zeolite appeared Br nsted acid sites, but support with the incorporation of silica soldid not appear Br nsted acid sites.Step-by-step impregnation method was used to prepare two series of sulfided dieselhydrotreating catalysts. Ni-Mo-P solution and ammonium tetrathiomolybdate-ethanolaminesolution were used as two kinds of impregnated solution.The experiments were carried out toinvestigate impact of impregnation sequence successively to the performance of dieselhydrotreating of sulfided catalyst. The evaluation results of FCC diesel hydrotreating showthe preferred impregnation sequence of reactive metal impregnation solution is first to impregnate Ni-Mo-P solution, followed by the solution of ATTM-ethanolamine, and throughthis procedure, the sulfided diesel hydrotreating catalysts exhibited the best catalytical activitytowards FCC diesel.The effects of calcination temperature was also investigated in roasting stage to analyzeactive metal dispersion and phase structure of sulfided catalyst. The crystalline phase andlamellae structure of MoS2were characterized by XRD(X-ray diffraction) and HRTEM (highresolution electron microscopy). Analysis showed that the active component was uniformlydispersed on the catalyst surface, and with the raise of the calcination temperature, thecrystalline phase of MoS2have undergone a partial aggregation, and the stacking number ofMoS2lamellae increased.Then the hydrotreating performance of two series of hydrotreating catalysts were testedon100ml high pressure pilot plant with the FCC diesel as feed. The evaluation results of FCCdiesel hydrotreating experiments indicated that under the conditions of the reactionhydrogen partial pressure of7.0MPa,reaction temperature of345℃, LHSV1.5h-1, V (H2)/V(Oil)=500,two series of catalyst have excellent hydrodesulphurization andhydrodenitrogeneration performance, among which NiMoS-400exhibited the high activity ofdesulfurization, with the HDS reaching97.2%, and the catalyst NiMoS-300had the highactivity of hydrodenitrogeneration, and the conversion of HDN was98.6%. The hydrorefiningperformance of NiMoP-ATTM/-Al2O3series catalyst is better than ATTM-NiMoP/-Al2O3series of catalyst.