In the process of petroleum refining, realizing the production and utilization of chemical raw materials is the common goal pursued by the petrochemical industry at present. The integration of the refining and chemical industry can not only produce clean fuel, but also meet the demand of the chemical industry for raw materials. In this study, Y zeolites with controllable crystal size and particle size were successfully prepared by simply adjusting the composition of the directing agent. Through a series of characterization, the effects of the composition change of the directing agent on the physicochemical properties of Y zeolites were investigated. Corresponding NiWS supported catalysts were prepared by using synthesized Y zeolites as supports. Taking naphthalene as the model reactant, the effects of crystal size and particle size of Y zeolites on the catalytic performance of the catalyst and on the hydrocracking of naphthalene to C6–C8 products were investigated. The results show that the preparation of small crystal Y zeolites can be realized by simply adjusting the composition of the directing agent, and the corresponding catalyst can realize the efficient production of chemical raw materials. This is expected to provide a simple, economical, feasible, and effective idea for the petrochemical industry to realize the goal of refining and chemical integration.
Dai Xiaojun,Cheng Yan,Si Meng,Wei Qiang,Zhou Yasong
The complexation-excessive impregnation modification method, which was original in this study, and the ion-exchange method and the in situ modification method were used to synthesize Ni-modified SAPO-11 molecular sieves. With the Ni-modified SAPO-11 samples as support, the corresponding NiWS-supported catalysts for the hydroisomerization of n-hexadecane were prepared. The effects of Ni-modification on SAPO-11 characteristics and the active phase were studied. The structure, morphology, and acidity of SAPO-11, as well as the interaction between active metals and support, the morphology, dispersibility, and stacking number of the active phase, were all changed by Ni-modification methods. The complexation-excessive impregnation modification method deleted a portion of Al from SAPO-11 molecular sieves while simultaneously integrating Ni into the skeletal structure of the surface layer of SAPO-11 molecular sieves, considerably enhancing the acidity of SAPO-11 molecular sieves. Furthermore, during dealumination, ethylenediaminetetraacetic acid generated more mesoporous structures and increased the mesoporous volume of SAPO-11 molecular sieves. Because the complexation-excessive impregnation modification method increased the amount of Ni in the surface framework of the SAPO-11 molecular sieve, it has weakened the interaction between the active phase and the support, improved the properties of the active phase, and greatly improved the hydroisomerization performance of NiW/NiSAPO-11. The yield of i-hexadecane of NiW/NiSAPO-11 increased by 39.3% when compared to NiW/NiSAPO-11. It presented a realistic approach for increasing the acidity of SAPO-11, reducing the interaction between active metals and support, and improving the active phase stacking problem.
The reason for high-difficulty nitrogen removal of aromatic N-heterocyclic compounds in petroleum fractions was investigated from the main thought of “NiWS property - Reaction behavior - DFT calculation”. The properties of the used catalyst were characterized by a series of techniques with the aim of providing the basis for model construction in the DFT calculations. The kinetic experiments in fixed-bed reactor revealed that although 1,2,3,4-tetrahydroquinoline (THQ1) and decahydroquinoline (DHQ), o-ethylaniline (OEA) exhibited relatively high yields in the HDN reaction of quinoline and indole respectively, they were all able to show high conversions and HDN rates when reacted as feedstocks alone. The study of product normalizations in the reaction system of the mixed feedstocks demonstrated that the difficulty of conversion of THQ1 and DHQ in quinoline HDN was mainly due to the inhibition effect of quinoline feedstock. While in the HDN of indole, the presence of the intermediate product OEA was the main factor for the low conversion of indole. This phenomenon of inhibition originating from within the molecular reaction network was proposed as N-N self-inhibition effect for the first time. The DFT calculations suggested that the inhibition of quinoline on THQ1 could be attributed to the adsorption advantage of quinoline, while the inhibition on DHQ was mainly due to the steric hindrance effect of DHQ itself. And the inhibition effect of OEA on indole can be mainly attributed to its greater nucleophilicity and stronger adsorption ability on the active sites compared with IND.
危险品化学品经营许可证（带存储）