Insight into the Fe2O3/CaO-based chemical looping process for biomass conversion

In this study, the looping materials of Fe2O3, CaO, mechanically mixed CaO and Fe2O3, and chemically synthesized Ca2Fe2O5 were tested for comparison of the performance and gas evolution processes. The reaction mechanism was illustrated to have an insight into the Fe2O3/CaO-based chemical looping process. Results found that the reduction from Fe2O3 to Fe3O4 trended to form CO2 while the transition of Fe3O4 to Fe happened after 650 °C was most likely to release CO. CO2 adsorption by CaO during 400–600 °C and further desorbed at higher temperature for CO2 Boudouard reaction which enhanced the biomass conversion. Mechanically mixed CaO and Fe2O3 maintained the properties of CaO and Fe2O3 with CO2 transfer and oxygen releasing during chemical looping reaction process, while the synthesized Ca2Fe2O5 presented hard reducibility which prefer to generate CO with the highest concentration (34.96 vol%) during chemical looping process at 850 °C. © 2020 Elsevier Ltd