Highly efficient CO2 enrichment integrated with H2 production from blast furnace gas via chemical looping

Blast furnace gas (BFG), a byproduct of ironmaking, rich in CO2 and CO, poses challenges for direct carbon emission reduction via conventional separation and purification technologies. Leveraging the intrinsic CO2 separation capability of chemical looping technology to obviate complex gas separation procedures offers a distinctive and promising approach. Herein, the transition metal oxides (manganese, cobalt, nickel, and copper) as modifiers for iron-based oxygen carriers (OCs) to enable chemical looping-driven CO2 enrichment and H2 production from BFG was investigated. The impacts of manganese (as a promoter) on the bulk and surface properties of OCs were systematically examined. Reactivity tests demonstrate that Mn-modified Fe-based OCs exhibit excellent activity for BFG conversion. Notably, the 10Mn/20Ce/Fe OC demonstrates the highest oxygen activity and enables a CO conversion of 99.83% and H2 yield of 2.45 mmol/g at 650 °C. Mechanistically, Mn ions incorporate into the CeO2 lattice to generate a strongly interacting Mn-O-Ce structure, which acts as a dynamic oxygen gateway to activate CO molecules. Meanwhile, Mn2O3 facilitates co-adsorption and expedites the reaction kinetics, which contributes to the high activity of the OC. Our findings regarding the formation of active oxygen, as well as the coupling of catalytic reactions and oxygen donation, provide a novel approach for designing efficient OCs. Overall, this study demonstrates the potential of CO2 enrichment and blue H2 production via chemical looping process of BFG conversion.