【摘要】 喷吹CO₂实现碳自循环利用以降低碳排放是具有潜力的新型减碳技术。文章研究高炉喷吹CO₂对风口燃烧状态影响，结果表明，随着CO₂喷吹量增加，煤粉起始和结束燃烧温度均明显升高。煤粉燃烧过程分为吸热脱除挥发分和残炭燃烧放热两个阶段。C与CO₂气化反应吸热降低了风口区热量，进而抑制了煤粉脱挥发分过程，最终使得回旋区末端温度显著升高。CO₂喷吹量每增加1 Nm³/t，理论燃烧温度降低约5.85 K，综合调整富氧率和燃料比以保持理论燃烧温度不变，富氧率相应增加约0.13个百分点，燃料比相应增加约1.2 kg/t。因实际冶炼过程富氧能力限制，以及燃料比增加导致经济成本提升的约束，通过外部加热提高CO₂喷吹温度是提高喷吹量的重要手段。更多还原

【Abstract】 Carbon self-recycling through CO₂ injection to reduce carbon emissions is a potential new carbon reduction technology. This paper takes blast furnace as an example to study the effect of CO₂ injection on tuyere combustion state. The results show that with the increase of CO₂ injection,the starting and ending combustion temperatures of pulverized coal increase significantly. The combustion process of pulverized coal is divided into two stages: endothermic devolatilization and residual carbon combustion exotherm. The gasification reaction of C and CO₂ endothermic reduces the heat of the tuyre,which further affects the devolatilization process of pulverized coal,and finally the temperature at the end of the swirl area is significantly increased. With the increase of CO₂ injection amount,the theoretical combustion temperature decreases. For every 1 Nm³/t increase of CO₂ injection amount,the theoretical combustion temperature decreases by about 5. 85 K. By comprehensively adjusting the oxygen enrichment rate and fuel ratio to maintain the theoretical combustion temperature,the oxygen enrichment rate is increased by about 0. 13 percentage points,and the fuel ratio is increased by about 1. 2 kg/t. Due to the limitation of oxygen enrichment capacity in actual smelting process and the economic cost of increasing fuel ratio,increasing CO₂ injection temperature by external heating is an important means to increase the injection volume.更多还原