Study On Moderate Hydrodesulfurization Of Fuel Oil And Molecular Simulation

In recent years, deep desulfurization of fule oils, for example diesel and gasoline, has attractedmore and more interests because exhaust gases containing sulphur oxides and nitrogen oxides area major cause of air pollution when they burning. There are two aspects to make desulfurizationof fuel oil more and more serious, on the one hand, people ask more demand about environment,on the other hand, the sulfur content in fuel oils will probably has rised in many countries thanthe past years because of the quality declining of the crude oil, which make it difficult to removesulfur compounds from fuel oils.In the present, hydrogenation desulfurization (HDS) is one of the most widely usedtechnologies for desulphurization, which is a catalytic chemical process to convert sulfurcompounds into H2S under high temperature and high pressure with presence of H2and catalysts.HDS has advantages as following, its simple operation and flexible handling of the raw materials.However, HDS was conducted under high temperature, high pressure, expensive catalyst anddifficulty to remove aromatic sulfur compounds, which restricts the further development ofhydrodesulfurization. Novel and high efficient catalyst operated under mild conditions should bedeveloped on desulfurization to overcome the above problems. The major work and researchresults of this treatise are as follows:(1) The Ni/Al2O3, Ni-Mo/Al2O3, Mo-Ni/ZSM, Mo-Co-Ce/ZSM, Mo-Ni-Ce/ZSM,[Bmim]PF6-Ni/SiO2,[Bmim]BF4-Ni/SiO2, Mo-Ni-Ce/ZSM+[Bmim]BF4catalysts were preparedby impregnation method and extrusion molding method. The XRD, SEM, EDS and BETtechniques were employed to investigate the structures and characteristics of the catalysts. Thetoken results show that the catalysts were prepared successfully.(2) The Ni/Al2O3catalyst was used in the hydrogenation of methylbenzene. The effects ofreaction temperature, pressure and reaction time were also investigated. The results indicated thatunder conditions of T=250oC, t=6h, P=3MPa, n=150r/min methylbenzene has the bestconversion rate. The Ni/Al2O3catalyst supported with [Bmim]PF6or [Bmim]BF4were used inthe hydrogenation of methylbenzene and naphthalene under the same conditions. The[Bmim]PF6-Ni/Al2O3has an excellent efficiency in the hydrogenation of naphthalene than[Bmim]BF4-Ni/Al2O3.(3) The Mo-Co/ZSM, Mo-Ni/ZSM, Mo-Co-Ce/ZSM, Mo-Ni-Ce/ZSM, Mo-Ni-Ce/ZSM+[Bmim]BF4, Mo-Ni-Ce/ZSM+[Bmim]PF6catalysts were used in the hydrodesulfurizationof dibenzothiophene (DBT) under conditions of T=250oC, t=6h, P=3MPa, n=150r/min. Theresults indicated that Mo-Ni-Ce/ZSM+[Bmim]BF4had the highest desulfurization ability. The catalyst supported with IL has a good job in the hydrodesulfurization of dibenzothiophene (DBT)than the catalyst without IL supported under the same reaction condition.(4) The hydrogenation of naphthalene and the desulfurization of thiophene were studied viamolecular simulation with the procedures of Dmol3in Materials Studio software. It was, foundthat ionic liquids have played an active role in hydrodesulfurization.In this paper, The catalysts supported with ILs were demonstrated to achieve positive effectson hydrogenation and desulfurization under mild conditions by experimental study andmolecular simulation.