Modelling and simulation of hydrodynamics in double loop circulating fluidizedbed reactor for chemical looping combustion process

Abstract

A multiphase CFD model has been developed and implemented in an in-house code for a coupled double loop circulation fluidized bed (DLCFB) reactor which can be utilized for the chemical looping combustion process. The air reactor and the fuel reactor were operated in fast fluidization regime and simulated separately, the connection between the two reactors is realized through specific inlet and outlet boundary conditions. This work represents a first attempt to model and simulate the novel DLCFB system. The model predictions of the axial pressure profiles are in good agreement with the experimental data reported in the literatures. In addition, typical core-annulus structure of radial solid volume fraction distribution can be well predicted in both reactors. These indicate the capability of the model for predicting the cold flow performance of the DLCFB system. Furthermore, the effects of superficial gas velocity, total solid inventory on the flow characteristics have been examined. The results show that an increase of the gas velocity could enhance the solid exchanges between the two reactors. The additional solids were accumulated in the bottom of the reactors when the total solid inventory was increased.