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.