Numerical simulation of a chemical looping combustion of biomass: Hydrodynamic investigation

In the present work, the multi-phase particle-in-cell (MP-PIC) method, implemented in OpenFOAM, is used to simulate a biomass-fueled chemical looping combustion (CLC) process in a circulation mode. Hydrodynamics of the gas-particle flow are analyzed, mainly, through pressure drop along the reactor, solid volume fraction distribution, the solid circulation between the two connected reactors, and gas and solid fuel leakages. Preliminary simulations agree well with the experimental data reported in the literature. Additional simulations using various fluidization rates into both the fuel and air reactors and different solid inventories are then performed. Results show the relevance of the pressure balance between the reactors to decreasing the gas leakage. Increasing the solid mass in the system has a favorable impact on preventing gas mixing but it allows solid fuel particles to leak to the air reactor. This is due to the increase of the solid circulation between the reactors, thus causing biomass particles' entrainment by the oxygen carrier particles. Simulation results also reveal the higher impact of the air reactor fluidization rate on the solid circulation, with respect to that of the fuel reactor fluidization rate.