Syngas and CO production via cyclic coke oven gas reforming and CO2 splitting with integrated experimental, economic, and environmental assessment

초록

A cyclic redox process integrating coke oven gas reforming (COGR) and CO2 splitting (CS) is proposed for the production of syngas and CO. The feasibility of this two-step cycle critically depends on the precise redox properties of metal oxides, enabling stable operation, energy conservation, carbon neutrality, and industrial scalability. This study evaluated the economic and environmental viability of the COGR-CS process based on experimental results using SrFeO3. Extent of reduction assessment revealed that SrFeO3 exhibited higher reactivity toward CH4 and efficient CO2-driven reoxidation under CH4 reforming-CS conditions, compared to Fe2O3. At coke oven gas (COG) emission temperatures, the productions of H2 and CO were enhanced by CH4 decomposition and the reverse Boudouard reaction, respectively. Partial-COGR experiments with controlled feed compositions demonstrated that CO2 in COG reoxidized oxygen vacancies in SrFeO3-delta during COGR. Quantitative analysis of reaction progress was consistent with the structural evolution of SrFeO3 and the carbon removal behavior during partial-COGR-CS. Long-term operation confirmed the stable production of syngas and CO, with high reoxidation (94.2 %), carbon removal (95.6 %), and CO2 conversion (99.6 %) maintained under redox equilibrium. Process simulation based on accurate redox properties aligned with equilibrium data, validating its predictive reliability. The integrated COGR-CS system (100 tonnes/day CO) achieved favorable cost (559.4 USD/ tCO) and CO2 intensity (1.015 kg CO2/kg CO) compared to CO2 electrolysis, owing to its direct thermal energy utilization and the conversion of greenhouse gases into value-added chemicals, offering a practical and scalable route to low-carbon, circular industry.

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