Investigation of a Coupled Fuel Reactor for Coal-Fueled Chemical Looping Combustion

Abstract

This work presents an experimental investigation and modeling study of a fuel reactor designed for in situ gasification chemical looping combustion (iG-CLC). The fuel reactor is designed to couple a bubbling fluidized-bed reactor and a downer reactor. The downer reactor can enhance gas–solid contact in the freeboard region and eliminate the unburned gases from the fuel reactor. The fuel reactor consists of an annular bubbling fluidized bed and a center-located riser. Cold-model experiments were conducted. The solids circulation rate and gas bypassing between the annular fluidized bed and the riser were studied. Experiments in a hot downer reactor were performed, and a two-dimensional model was developed and validated with experimental data. The verified model shows that a downer reactor with proper solids dispersion can eliminate more than 78% of the fuel gas exiting the fuel reactor with an overall solids dropping rate of 8 kg/m2·s.