Modelling textural and mass transfer properties for gamma-alumina catalysts using randomly generated pore networks

A Monte Carlo approach is used to generate 2D and 3D networks of randomly connected cylindrical pores with a variety of configurations. These networks are created to represent the gamma-alumina supports of hydrotreating catalysts. Textural properties from generated pore networks are compared with experimental values of porosity, specific surface area, and specific pore volume. The experimental properties were estimated using a helium pycnometer and nitrogen sorption isotherms for five gamma-alumina samples. Simulated and experimental textural properties concur. Internal diffusion is simulated by 1D Fick diffusion within each pore of the network. A macroscopic diffusion parameter for vacuum distillate type molecules, previously obtained by inverse liquid chromatography and by pulsed-field gradient nuclear magnetic resonance experiments on alumina samples, is predicted and confronted with experimental values. Diffusional properties are in good agreement when considering two hierarchically organized porous domains.