Combustion Performance of Sewage Sludge in a Novel CLC System with a Two-Stage Fuel Reactor

Abstract

Chemical looping combustion (CLC) is a promising and efficient technology for sewage sludge (SS) combustion with carbon capture. The CLC reactor configuration is crucial to the intimate contact between the solid phase and the gas phase species. This work proposed a novel CLC unit with a two-stage fuel reactor. Different from the conventional CLC unit with a single-stage bubbling bed as fuel reactor, two-stage fuel reactor design can make gas phase and solid phase be in adequate contact and achieve gas flow redistribution in the fuel reactor. On this unit, both cold and hot experiments were conducted. The gas-solid flow characteristics were studied on the cold model, and the system was successfully commissioned and in stable operation. No gas leakage occurred between reactors. In the hot experiments, SS from the municipal wastewater treatment plant was chosen as solid fuel and hematite with a size range of 0.3–0.45 mm was used as oxygen carrier. To thoroughly evaluate the performance of this noval CLC syst...