Development of CO₂ capture and utilization technology in steelmaking plant

The performance of a recycling process for CO₂ capture and utilization of exhaust gas in the steelmaking plant was reported. A facility capable of capturing CO₂ at 3200 m³/h was established in the steelmaking plant, resulting in the CO₂ production of 50,000 t/a. The CO₂ concentration of the exhaust gas from the lime kiln increased from 25.0 to 99.8 vol.% using the comprehensive method of the pressure swing adsorption and cryogenic separation. The captured and purified CO₂ was successfully applied in the converter process by the top blowing and bottom blowing. The utilization of CO₂ was 3.5 m³/t through these two modes. After optimizing parameters of CO₂–O₂ mixed top blowing, the value of [C] × [O] and the content of TFe in slag were reduced by 1.33 × 10⁻⁴ and 1.27%, respectively, and the dephosphorization rate of the molten steel increased by 2.31%. For the CO₂ bottom blowing, the [N] content in the molten steel was significantly reduced by 5.7 × 10⁻⁶.