卟啉氧钒在均一孔结构模型催化剂中的扩散

利用孔结构均一、孔隙率和曲折因子固定的CoMo/Al₂ O₃ /SiO₂模型催化剂，研究了加氢催化反应条件下渣油加氢脱金属过程中金属有机化合物八乙基卟啉氧钒（VO-OEP）在模型催化剂孔道中的扩散过程。结果表明，在反应压力6.0 MPa、反应温度270~330℃的加氢反应条件下，VO-OEP的有效扩散系数（D_e）范围为0.45×10^-10~2.33×10^-10m²/s，且其值随着温度升高以及催化剂孔径的增大而增加，并估算出反应条件下VO-OEP的体相扩散系数，指出由此法测得的体相扩散系数比采用Wilke-Chang和Stokes-Einstein等经验公式估算而得的体相扩散系数更接近于反应条件下的分子体相扩散系数。

Diffusion of Vanadyl Octaethylporphyrin in Well-Defined and Uniform Pore-Structure Model Catalyst

The intraparticle diffusion of vanadyl 2,3,7,8,12,13,17,18-octaethylporphyrin (VO-OEP) was investigated under hydrodemetallization reaction of heavy oil over well-defined and uniform pore-structure (WDUPS) CoMo/Al₂O₃/SiO₂ model catalysts. Based on the intrinsic reaction rate constant and apparent reaction rate constant, the intraparticle effective diffusivity (D_e) of VO-OEP was calculated, which ranged from 0.45×10^-10 to 2.33×10^-10m²/s under the reaction conditions of 270-330℃ and 6.0 MPa. Higher reaction temperature and larger pore size of catalyst led to larger D_e of VO-OEP. The bulk diffusivity of VO-OEP under reaction condition was obtained by extrapolation method based on kinetic data. The bulk diffusivity values thus obtained were more approximate to the reaction situation compared to those estimated by Wilke-Chang and Stokes-Einstein formulas.