Canadian Journal of Chemical Engineering, Vol.93, No.6, 1033-1043, 2015
Numerical evaluation and improvement efficiency of radial flow moving-bed reactors for catalytic pyrolysis of light hydrocarbons to low carbon olefins
A three-dimensional (3D) reactor model based on the Eulerian-Eulerian approach was applied to describe the gas-solid flow and heat transfer performance in a radial flow moving bed reactor (RFMBR). A six-lumped kinetic model for the catalytic pyrolysis of C-4 hydrocarbon was employed. The heat transfer characteristics and species concentration profiles were investigated in the reactor under various reaction conditions. Effects of operation parameters and reactor structures on the reactor performance were also evaluated and optimized numerically. Simulation results show that there exists a good heat transfer performance between gas and solid phases in the catalyst bed. The temperature profiles and the species yield distributions are different with respect to bed height positions. Moreover, the results indicate that product yield is more sensitive to the reaction temperature than to the dilution rate and the reaction residence time. For the Z-type centripetal flow RFMBR, an annular tube with an inverted cone structure is helpful to improve the uniformity of flow distribution and increase low-carbon olefins yields.