Review on CO terminal treatment technologies in steel industry

This paper reviews the methods for terminal treatment of CO components in the exhaust gas of the steel industry, including liquid absorption, solid catalytic and plasma oxidation method. High equipment cost for liquid absorption method and is limited by the energy consumption. Noble metal catalysts are expensive. Transition metals are cheap and widely used for the high efficiency, but the water resistance is poor. Plasma catalytic oxidation is rarely used alone due to uncontrollable products. Each technology is difficult to meet production requirements, so a combination of multiple technologies is adopted. Several processes were used to improve the hydrophobicity of transition metals. Hydrophobic coatings are difficult to balance reactivity and hydrophobicity, and reagents are expensive. Adding dissimilar metal atoms cannot adapt to high humidity environments for a long time. The plasma coupled catalytic process cannot completely eliminate the deactivation when encountering water. This paper focuses on the catalyst modification technology, analyzes the mechanism of water intoxication on the catalyst surface, summarizes the factors affecting the surface activity and finally predicts the change of surface bonding strength based on the HSAB theory, making prospects for the development of catalyst modification theory，and finally estimate the promotion of HSAB theory in production practice. [Display omitted] •Characteristics of CO terminal treatment methods and future direction.•Summarizes previous conclusions and deficiencies on deactivation mechanism of metal catalysts in moist gas.•Effect of plasma discharge on mechanism of CO oxidation.•Discharge environment improving catalyst water resistance.•Basic study on the surface selectivity of CO catalysts and proposing new possibilities.