Numerical investigation of solid circulation flux in an internally circulating fluidized bed with different gas distributor designs

Abstract

Numerical simulations using two-fluid model incorporating the kinetic theory of granular flow (KTGF) are conducted to study the behavior of bed particles in a two dimensional baffle type internally circulating fluidized bed (ICFB). Complete knowledge of the solid circulation flux in an ICFB is very important as the bed particles are continuously circulating between different chambers above and below the central baffle. The effects of the gas distributor types, superficial fluidizing velocity and chambers height elevation difference are evaluated through computer simulations and the results are quantified in terms of solid circulation flux. By increasing the gas velocity (Uf) in the RC chamber, solid circulation flux from the heat exchange chamber (HEC) to the reaction chamber (RC) through the slot under the baffle is increased regardless of the distributor design. From further investigations, the solid circulation flux and particles radial velocity through the slot in the tubular gas distributor ICFB are found to be considerably increased as compared to the other configurations in our case. The elevated RC distributor is found to have a little impact on the solid circulation flux as a function of Uf. By varying RC distributor elevation while keeping HEC constant, the circulation flux is also changing and the highest flux is observed at an elevation level of 90mm.