Mathematical Modeling of the Adsorption-Catalytic Process with Internal Heater in a Multisectional Arrangement

In this work, a multisectional reactor for the adsorption-catalytic process for the neutralization of emissions from volatile organic compounds (VOCs) was studied by the method of computational fluid dynamics (CFD) modeling using the COMSOL Multiphysics commercial software. The nonstationary model in a three-dimensional (3D) geometry considered the change in the velocity field, pressure, and mass balance, including in the pores of the catalyst pellets and the reactions on their inner surface, as well as the heat balance, taking into account the ongoing reactions. Cases with 1, 2, and 5 sections were considered; it was shown that system sectioning allows not only to reduce the peak temperature of the exhaust gases and the peak concentration of VOCs in them at the regeneration stage but also to increase the average VOC abatement degree. The phenomenon of a self-sustained decrease of the gas flow rate in the section undergoing autothermal adsorbent–catalyst regeneration, improving process efficiency, was studied. Various materials of internal walls were also considered; it was found that the use of materials with the minimum possible thermal conductivity is preferable.