Experimental And Numerical Modeling Studies Of The MTP Reaction Kenetics Over The Monolithic SS-fiber@HZSM-5 Core-shell Catalyst

In this work, through the technology of direct growth of zeolite crystals on the thin-sheet 3D sinter-locked metal microfibrous network structure, we synthesized the monolithic SS-fiber@HZSM-5 core(SS-fiber)-shell(HZSM-5 zeolite layer) catalyst for the experimental and numerical modeling studies of MTP reaction kinetics, and revealed the reason why the catalytic activity/selectivity of the monolithic SS-fiber@HZSM-5 was better than the powdered HZSM-5 on the aspect of kinetics.Kinetic experiments for MTP process over the monolithic SS-fiber@HZSM-5 and traditional unstructured powdered HZSM-5 were respectively carried out in a continuous flow fixed-bed reactor. The kinetic data were obtained by measuring the evolution of product distribution with different space time at 400℃,420℃,450℃ and 480℃. In comparision with the powdered HZSM-5 catalyst, the monolithic SS-fiber@HZSM-5 catalyst had higher diffusion efficiency and narrower residence time distribution, which could not only inhibit ethylene formation and promote propylene yield but also improve the utilization efficiency of the HZSM-5 zeolite by a factor of ～6.On the basis of the dual-cycle reaction mechanism, a MTP lumped kinetic model was established, which showed the evolution of individual olefin and reflected the main reaction path. It included methanol, dimethyl ether, ethylene, propylene, butene, pentene, hexene, methane, C2-C6 alkanes, C7+, a total of 10 components and 19 reactions. The experimental data were fitted by MATLAB software, and the lumped kinetic model was considered to be suitable because the calculated and experimental values of the product distributions basically fitted well, and the model identification met requirements. In addition, the obtained kinetic parameters could be applied to the reactor simulation and optimization of reaction conditions.