Thermodynamic evaluation and experimental investigation of CaO-assisted Fe-based chemical looping reforming process for syngas production

摘要

Many works have focused on the reactivity and valence transition of Fe-based oxygen carriers in chemical looping partial oxidation reforming process. However, the reforming performance and impacts of operating factors are unclear with the co-feeding of CaO being CO2 carrier to realize simultaneous CO2 capture and utilization. In this work, thermodynamic equilibrium calculation, reactivity test and material characterization are carried out to optimize the process characteristics. The impacts of feeding conditions (Fe/Al weight ratio, methane amount, Ca/Fe mole ratio and packing manner) on the reforming reactivity are obtained to reveal the interaction between CaO and Fe2O3. The gas product distribution indicates that the carbon deposition and oxidation degree is closely related to CH4 amount. The spatial configuration between CaCO3 and Fe2O3 reforming is essential to obtain the desirable reforming products. The difference of FeO existence on the theoretical and experimental phase components illustrates that reaction degree is affected by the reduction agent amount. By comparing the methane temperature-programmed reaction of CaCO3, Fe2O3 and their mixture, it is suggested that the existence of CaCO3 is beneficial for accelerating iron-based methane reforming. This study provides a way to improve reaction degree and optimize process characteristic for chemical looping reforming process.