Coal direct chemical looping combustion process: Design and operation of a 25-kWth sub-pilot unit

► Successful long term (>230 h) demonstration of 25-kWth CDCL sub-pilot unit. ► Demonstrated recyclability of oxygen carrier in the sub-pilot unit operation. ► 97% Sub-bituminous coal conversion. ► >99% CO2 purity in reducer. ► No needs for solid recirculation device and additional carbon separation unit such as carbon stripper.