Synthesis Of SAPO-11/KIT-6 Micro-Mesoporous Materials And Their Applications In The Hydrodesulfurization Of FCC Gasoline

With the deteriorating quality of oil products,the emission of pollutants caused by oil combustion becomes more and more serious.The environmental protection regulations formulated by many countries for the quality of oil products have become more and more stringent.The key to the improvement of oil quality lies in the research and development of clean oil technologies.Hydrodesulfurization（HDS）technology is currently the most commonly used method for removing sulfur from oil products.The key to improving desulfurization efficiency is the development of high-efficiency catalysts.At present,CoMo/γ-Al₂O₃ catalysts are commonly used in the industry,but the catalysts can’t meet the requirements for the deep removal of sulfur-containing compounds.Therefore,it is necessary to develop new and highly efficient catalysts for HDS reaction.The research work of this dissertation started from the four aspects for the designing and preparing of novel and efficient catalysts including the preparation of the support,the loading of active components of NiMo,the atomic doping of support skeleton,and modification of catalysts.The prepared support materials,catalysts and their physicochemical properties were characterized and analyzed by using a series of analytical methods such as XRD,BET,UV-Vis DRS,SEM,and TEM.The catalytic performances of the composite SK-supported NiMo catalysts were evaluated for HDS of the model compound DBT.In this dissertation,a novel micro-mesoporous composite material was firstly prepared.After confirming the preparation process of SAPO-11 microporous molecular sieve,we successfully synthesized composite SK molecular sieve material,which simultaneously contains the skeletal structures of SAPO-11 and KIT-6 by using SAPO-11 microcrystalline emulsion precursor as raw material and P123 as a template agent.It was determined that the best composite SK molecular sieve carrier was obtained when the amount of SAPO-11 microcrystalline emulsion was 10%.The effect of supported NiMo active component on the catalytic performance for the HDS of model compound DBT was investigated.It included three aspects of the impregnation sequence of NiMo active components,the atomic ratio of Ni to Mo,the loading amount of NiMo active components.It was determined that the optimal conditions for the obtaining the best catalysts for HDS of DBT are as follows.When the impregnation method of the active component was simultaneous impregnation of NiMo,the atomic ratio of the active component Ni to Mo was 0.4,the loading amount of the active component NiMo was 15%,the catalyst obtained under aboved conditions gave the highest HDS reaction activity,and the desulfurization rate reached 93.8%.The effect of doping Ti atoms into the framework of molecular sieve support on the catalytic performance for the HDS of model compound DBT was investigated.It was found that the doping of Ti atoms into the framework of molecular sieve supports is favorable for the dispersion of the active components,which is beneficial to the improvement of the desulfurization performance of the catalyst.When the doping amount of Ti was 2%,the highest HDS activity of the catalyst was obtained,and the desulfurization rate was 94.9%.The effect of P modification on the catalytic performance for the HDS of model compound DBT was investigated.The addition of P element to the catalyst modifies the acid amount and acid strength of the catalyst,and the HDS performance of the as-prepared catalyst is improved.It was found that the acid amount of the P-modified catalyst increased.Moreover,P modification is helpful for the formation of hexacoordinated active Mo species.When the addition amount of P element was 1%,the performance for HDS of DBT model compounds was the best,and the desulfurization rate reached 96.4%.