Typical Case of Converter Smelting with High Cooling Ratio in Chinese Iron and Steel Enterprises: CO2 Emission Analysis

In this study, the effects of using different scrap ratios in a converter on carbon emissions were analyzed based on life cycle assessment (LCA) theory, and the carbon emissions from the converter were evaluated with the use of coke and biochar as heating agents at high scrap ratios. In this industrial experiment, the CO2 emissions during the converter smelting process decreased with the increase in the scrap steel ratio. For every 1% increase in the scrap steel ratio, the carbon emissions during the steelmaking process decreased by 14.09 kgCO2/t steel. Based on statistical data for the actual use of a charcoal heating agent in the converter, the relationship between the utilization coefficient of the heating agent and the scrap ratio was calculated as η=7.698×102x−2.596. When biochar was used as a converter heating agent, the scrap ratio required to achieve the lowest carbon emissions was 36%, and the converter emissions could be reduced by 172 kgCO2/t·steel relative to the use of coke. The use of biochar as a converter heating agent can contribute to the elimination of 330 million tons of scrap through furnace–converter long-process steelmaking, yielding an annual reduction in CO2 emissions of 158 million tons.