The article discusses a new method called chemical looping combustion (CLC) that can help reduce CO2 emissions from burning fuels. This method uses a solid oxygen carrier to transfer oxygen from the air to the fuel without mixing them directly. By doing this, it can reduce the formation of harmful gases like NOx. The researchers propose using a combination of a circulating fluidized bed (CFB) and a moving bed to make CLC work with solid fuels like coal and biomass. This approach faces challenges like separating the oxygen carrier from the fuel and dealing with ash and unburned carbon particles. The study introduces an innovative concept to address these challenges and make CLC suitable for solid fuels.