Experimental evaluations of solid-fueled pressurized chemical looping combustion – The effects of pressure, solid fuel and iron-based oxygen carriers

Coal-based Pressurized Chemical Looping Combustion Combined Cycle (PCLC-CC) is the second generation of coal-fueled CLC plant, which possesses much higher plant efficiency and lower-CO₂ capture cost compared to the first generation - Coal-based CLC combined solely with steam cycle. PCLC-CC has a similar plant configuration to the Pressurized Fluidized Bed Combined Cycle (PFBC), and is composed of a PCLC Island, gas turbine, Heat Recovery Steam Generator (HRSG) and steam cycle. In the fuel reactor of PCLC Island, the metal-based oxygen carrier (OC) supplies oxygen for coal combustion and in-situ CO₂ capture. The air reactor of PCLC Island, where the OC is re-oxidized by air, serves as a combustion reactor to produce oxygen-depleted air of high temperature and high pressure to drive the gas turbine and the following steam cycle for large-scale power generation. This research provides an initial understanding of the complex reactions in the fuel reactor of the solid-fueled PCLC Island in the pressures range of 1–6 bars. Experiments conducted in the TGA apparatus and the fixed- and fluidized-bed reactors demonstrated the effects of operational pressure, coal char reactivity and different iron-based OCs behavior on the performance of PCLC.