Understanding of chemical looping with autothermal operation

Abstract

Chemical looping combustion (CLC) is under development for fuel combustion, an art of technology in terms of less energy penalty for CO₂ removal. In addition to the oxygen carrier (OC) development, the autothermal operation is another key for the success of CLC, which is mainly determined by a difference of heat of combustion per mole O₂ between the fuel and oxygen carrier (dQ_Fuel-OC). Ideally, the developed OC should have dQ_Fuel-OC > 0, that is, the coupling of OC-fuel needs to be evaluated at the beginning to check the feasibility of autothermal operation.

The advantages and developments of CLC have been well-reviewed by Henderson and recently by Lyngfelt, Abuelgasim et al., Abdalla et al., and Adánez-Rubio et al., as well as by a handbook. In this communication, the feasibility of autothermal operation of CLC is systematically analyzed. The selection of OC to couple with fuel, capacity of OC, impact of OC support materials, circulation rate of OC (mass and heat), heat-up of feeds, impact of aeration gas, reaction kinetics, and operation of CLC are discussed, aimed at providing some insights and approaches in the development of OC, which is, in any situation, fuel-determined. More attention is needed so that the CLC process can be operated in an autothermal mode and scaled up commercially in the future for CO₂ removal.