Preparation Of Ni-based Meso-and Macro-porous Sorbents And Performance For Diesel Desulfurization

As people environmental protection consciousness to strengthen, diesel desulfurization technology is becoming more and more attention. At present the method reduce the sulfur content in diesel oil hydrogenation desulfurization and hydrodesulfurization. Hydrodesulfurization technology requires high temperature and high pressure, hydrogen environment and precious metal catalysts such as strict conditions, equipment investment and operation cost is relatively expensive, and sulfide thiophene and its derivatives for polycyclic removal difficult. Adsorption desulfurization is a new effective method of removing sulfide in FCC diesel oil, has simple operation, less investment cost, no pollution, suitable for deep desulfurization, etc, it is a broad space for development and application prospects of new technology.（1） The mesoporous and macroporous alumina support was successfully prepared using PS colloidal crystals and co-polymer P123 as the dual templates. A series of high-performance X%NiO_x/Al₂O₃ adsorbents were prepared using mesoporous and macroporous alumina for adsorptive desulphurization（ADS） of commercial diesel（total sulphur content, 150 ppmw） at atmospheric pressure. Among the synthesized adsorbents, the reduced mesoporous and macroporous 20%NiO_x/Al₂O₃（Re20%NiO_x/Al₂O₃） presented the breakthrough capacity of 1.47 mg-S/g-sorbent with sulphur level of 10 ppmw. The ultra-deep desulphurization properties for two adsorbents were evaluated using simulated fuels. The adsorbent with macropores showed a superior desulphurization performance, and the existence of macropores remarkably increased its breakthrough capacity as well as improved the space steric hindrance effect. The adsorbents synthesized were characterized by Py-FT-IR and NH3-TPD techniques. The results showed that the synthesized adsorbents were stable, contained acid sites, especially Lewis acid sites, which played an important role in ADS. Even after three cycles of regeneration, the organic sulphur-adsorption capacity of Re20%NiO_x/Al₂O₃ was more than 80%.（2） MSN（silicon dioxide spherical particles） has been synthesized in alkaline condition by using TEOS（tetraethyl orthosilicate） as original silica source. A series of 20wt%La_xNi_yO_z/MSN sorbents were prepared by a sol–gel method which is used for test desulfurization performance to 150 ppmw sulfur content of commercial diesel. By the optimization of the La/Ni atomic ratios, 20wt%La₂Ni₈O_z/MSN performed the best at 25 oC with effective sulfur capacity of 0.598 mg-S/g sorbents. The results indicated the desulfurization performance of lanthanum is better than that of nickel. The BET, XRD, H2-TPR, SEM and HRTEM techniques were employed to characterize the support, fresh and used sorbents. The results indicated that composition and structure of the sorbents has important influence on the desulfurization performance during the desulfurization reaction.