Parametric and dynamic studies of an iron-based 25-kW th coal direct chemical looping unit using sub-bituminous coal

•Integrated, moving bed chemical looping reactor with iron-oxide based oxygen carrier.•Coal carbon conversion from 84.8% to 99.9%, thermal capacity 7.4 to 27.7kWth, O2 demand less than 1.3%.•Dynamic temperature of moving bed reducer is established and tracked during coal injection.•CH4 and CO present at initial coal injection, eliminated after oxygen carrier activated.•Lower coal injection had higher volatiles residence time and conversion.