Enhancing Oxygen Savings and Carbon Dioxide Purity in Biomass Oxy-Circulating Fluidized Bed Combustion with an Oxygen Carrier

•Oxygen carrier is applied to supply some O2 in a biomass OCA-Oxy-CFBC.•CO emissions decrease to 59% when silica sand is replaced with iron ore.•Adding an oxygen carrier achieved an O2 saving of 4.86%•CO2 purity increased to 97.4% without reduction of combustion efficiency.