Ash Interaction with Two Cu-Based Magnetic Oxygen\nCarriers during Biomass Combustion by the Chemical Looping with Oxygen\nUncoupling Process

Chemical-looping\ncombustion (CLC) stands out as a promising method\nfor carbon capture and storage for the purpose of mitigating climate\nchange. The process involves the conversion of fuel facilitated by\nan oxygen carrier, with the resulting CO<sub>2</sub> inherently separated\nfrom other air components. Notably, when applied to biomass combustion\nthis process offers a pathway to achieving negative CO<sub>2</sub> emissions. However, a significant challenge for CLC, particularly\nin its application to biomass, is the management of interactions between\nash and oxygen carriers. Biomass-derived ashes typically contain substantial\nquantities of reactive ash-forming substances, such as alkaline and\nalkali earth elements. These interactions can impact the performance\nand longevity of the oxygen carrier, necessitating careful consideration\nand mitigation strategies in CLC systems utilizing biomass feedstocks.\nThis study examined the interaction between biomass ash components\nand two recently developed oxygen carriers, Cu30MnFekao7.5 and Cu30MnFe,\nduring combustion in a 1.5 kW<sub>th</sub> continuous unit. Both oxygen\ncarriers achieved 100% combustion efficiency and a CO<sub>2</sub> capture\nefficiency of 95% at 900 °C. Although the copper in both oxygen\ncarriers did not exhibit any noticeable interaction with ash components,\nthe accumulative presence of potassium and magnesium in Cu30MnFekao7.5\nwas identified by inductively coupled plasma and scanning electron\nmicroscopy with energy dispersive X-ray analysis, indicating an increase\nin the amount of both elements in the particles after combustion operation.\nNo problems of agglomeration or fluidization were observed in any\nof the experiments.