Transient reacting flow simulation of spouted fluidized bed for coal-direct chemical looping combustion with different Fe-based oxygen carriers

Coal-direct chemical-looping combustion (CD-CLC) is a next generation combustion technology that shows great promise as a solution for the need of high-efficiency low-cost carbon capture from fossil fueled power plants. To realize this technology on an industrial scale, the development of high-fidelity simulations is a necessary step to develop a thorough understanding of the CLC process. In this paper, simulations of multiphase flow in a CD-CLC process with chemical reactions are performed using the ANSYS Fluent CFD software. Discrete Element Method (DEM) provides the means for tracking the motion of individual metal oxide particles in the CD-CLC system as they react with the fuel and combine with CFD for capturing the solid-gas multiphase hydrodynamics. The overall results of the coupled CFD/DEM simulations using Fe-based oxygen carriers reacting with gaseous CH4 demonstrate that chemical reactions have been successfully incorporated into the CFD/DEM approach. The simulations show a strong dependence of the fluidization performance of the fuel reactor on the density of bed material and provide important insight into selection of a right oxygen carrier for the enhanced performance. This work provides the foundation for future simulations of CD-CLC systems using solid coal as fuel, which will be crucial for successful deployment of CD-CLC technology from the laboratory scale to pilot and industrial scale projects.