Catalytic oxidation of CO coupled with selective catalytic reduction (SCR) Denitrification: An alternative supplemental heating strategy and catalyst Design

The control of carbon monoxide (CO) emissions in sintering flue gas and their energy recovery are critical for improving air quality and promoting the green development of the steel industry. In this study, the feasibility of a heat supply scheme for SCR denitrification systems using catalytic oxidation of CO (COC) through Aspen Plus process simulation was validated, demonstrating its potential for practical application. When the CO concentration in the flue gas exceeds 0.4 vol %, the heat released from the complete oxidation of CO can satisfy the demands of selective catalytic reduction (SCR) denitrification. A comprehensive benefit analysis demonstrated that the COC heat supplementation scheme significantly reduced blast furnace gas consumption and usage costs by 2–3 orders of magnitude while lowering annual CO₂ emissions by approximately 40 %. To reduce the cost of catalysts in COC scheme applications, a highly active catalyst with ultra-low Pt loading was developed. Under ultra-low Pt loading of 0.01 wt %, the catalyst achieved complete CO oxidation at 210 °C. The turnover frequency (TOF) of 0.01Pt/Ti-D N₂ at 230 °C was 49.81 s⁻¹, representing a two-order-of-magnitude improvement compared to the conventional 0.1Pt/Ti catalyst (0.1 s⁻¹). Characterization results revealed that the defective structure and fully exposed Pt clusters enhanced the catalyst's ability to adsorb CO and oxygen (O₂), creating favorable conditions for the CO oxidation reaction.