Porous-media model based particle-resolved simulation of a fixed bed with olefin catalytic cracking reaction

Understanding the interstitial reacting flow in particle packing structure and its relation with the reaction performance is crucial to designing a highly efficient fixed bed reactor. This study uses a particle-resolved approach with a porous-media model-based immersed boundary method to simulate an olefin catalytic cracking (OCC) fixed bed with 150 cylindrical particles by combining a six-lump kinetic model and mass transfer model. The effects of weight hourly space velocity (WHSV) and particle shape are further investigated in analyzing conversion, concentration variation, flow structure and pressure drop. The study reveals a three-stage pattern in variation of product concentration along the packing structure height with different WHSVs, providing the basis for determining the optimal packing height. It also finds that the hollow-cylindrical particle manifests the best reaction performance while the cylindrical particle the worst. The coordination of surface area and pressure drop of the packing structure determines the OCC reaction effectiveness.