Chemical looping with oxygen uncoupling of municipal solid waste with Cu-Ca composite oxygen carriers

To investigate the effects of Ca-doping on the characterization and thermal behavior of chemical looping with oxygen uncoupling (CLOU) of municipal solid waste (MSW), three Cu-Ca composite oxygen carriers (OCs) were prepared using mechanical mixing and self-assembly template synthesis (SATS). XRD results showed that the crystal phases and chemical state of CuO reverted to their initial state after redox cycles. H2 temperature-programmed reduction and thermogravimetric analysis indicated that 7.5 % Ca-doping enhanced reactivity and oxygen decoupling rate, with CuO@CaO/ZrO2-DW achieving the highest decoupling rate of −2.08 %/min. Catalytic activity was observed between 330 °C and 400 °C, while combustion enhancement was noted at 950 °C. 1:30 MSW-to-OC ratio was the most appropriate. The Cu-Ca composite OCs prepared by the SATS method exhibited excellent dispersion, and Ca doping alleviated Cu/CuO enrichment on the particle surface without significant agglomeration during 10 redox cycles. Kinetic analysis indicated that the chemical order model effectively describes the first stage, while the geometrical contraction model fits the second stage, with activation energies of 55.63–92.08 kJ/mol and 247.83–321.77 kJ/mol, respectively. These findings demonstrate that Cu-Ca composite OCs are excellent and stable candidates for CLOU applications.