Study on effect of gas distributor in fluidized bed reactors by hydrodynamics-reaction-coupled simulations

Abstract

Deep understanding of the complex relationship between the complex hydrodynamics and reactor performance in a reactive gas-fluidized bed is crucial to optimization of engineering design and industrial operation. In this work, multiphase particle-in-cell (MP-PIC) simulations coupled with reaction kinetics models are conducted to investigate the effect of gas distribution on reactor performance. A batch fluidized bed reactor with different distributors for regenerating spent FCC catalyst is simulated under different superficial gas velocities. In all simulation cases, the air flowrate and the spent catalyst inventory are kept constant. The results show an indiscernible effect of superficial gas velocity, but the induced-maldistribution conditions generally deteriorate the reactor performance. In addition to wall-slug formation, solids holdup, and slip velocities also decrease significantly in the plugged-gas distribution cases. Strong linear relationship between hydrodynamics and reactor performance are established. Present study sheds light on the importance of uniform gas distribution in industrial fluidized bed reactors.