Eulerian Simulation of a CLC Reactor

This chapter describes the application of Eulerian-Eulerian two-fluid method for simulation of the flow and reactions in a dual-fluidized bed chemical looping combustion based on the 300 W laboratory-scale experiment of Abad et al. (Fuel 86(7–8):1021–1035, 2007. https://doi.org/10.1016/J.FUEL.2006.09.021 ). The oxygen carrier is modeled as an Eulerian fluid phase based on the kinetic theory of granular flow. Chemical reactions in the fuel reactor for the reduction of the oxygen carrier are implemented in the simulation based on available reaction rate data for the reduction of hematite. 2D and 3D models are developed and detailed flow hydrodynamics and reaction performance are compared. Since diffusion is in an inherently 3D process, the shortcomings of the 2D simulation for a CLC reactor are exposed. On the other hand, the 3D model displays significantly improved results for the concentrations of the gases at the outlet produced by the reduction of metal oxide in the fuel reactor compared to the experiment, although some discrepancies are still present in the case of CO2. It is expected that the simulation accuracy can be improved significantly if more accurate empirical reaction rate data becomes available for the specific oxygen carrier and fuel considered.