Abstract:

The iron and steel industry accounts for 14%—18% of the total carbon emissions in China, making it the highest emitting sector in the industrial field. The blast furnace-basic oxygen furnace process contributes to 89% of the total steel production in China. This process is characterized by a long flow path and emits 2 tons of carbon per ton of steel produced. Carbon emission reduction based on the blast furnace-converter process is key to the steel industry's decarbonization goals. Based on the energy balance model, this study focuses on analyzing the impact of using coke oven gas and reformed coke oven gas for blast furnace injection on process parameters such as direct reduction degree and theoretical coke ratio. It aims to systematically evaluate the potential carbon dioxide emission reduction benefits of this approach. The results indicate that increasing the injection volume and temperature of hydrogen-rich gas effectively reduces coke consumption. However, under the same injection volume conditions, increasing the hydrogen purity leads to a slight increase in coke consumption due to heat compensation. When the coke oven gas is reformed to yield hydrogen gas with a purity of 97.9%, a carbon reduction of 34.62% in the blast furnace can be achieved. Compared to direct injection of coke oven gas, the potential for carbon reduction is increased by 17.76%. The carbon reduction mainly stems from the decrease in coke consumption and the reduced carbon content in the injected gas. Power generation from blast furnace gas is also a crucial step in carbon reduction. When the hydrogen purity of the injected gas is increased from 59% to 97.9%, the carbon reduction potential in this step is improved from 9.04% to 10.85%. The reformation of coke oven gas in the blast furnace injection process has the potential to surpass the upper limit of carbon reduction achievable with hydrogen-rich gas, making it a promising approach with potential for widespread implementation.

Key words: model, coke oven gas, carbon dioxide, hydrogen, carbon emission reduction

摘要：

钢铁行业碳排放占我国碳排放总量的14%~18%，是工业领域排放量最高的部门。高炉-转炉工艺钢铁产量占我国钢铁总产量的89%，工艺流程长，吨钢碳排放达2 t。基于高炉-转炉工艺的碳减排是钢铁行业实现脱碳目标的关键。基于能质平衡模型，分析焦炉气及重整焦炉气用于高炉喷吹对高炉直接还原度、理论焦比值等工艺参数的影响，系统评估该工艺有望产生的高炉二氧化碳减排效益。结果表明，提高富氢气喷吹量和温度可有效降低焦比；而相同喷吹量条件下提高氢纯度，由于热补偿原因，焦比会有所上升。当焦炉气被重整为97.9%的富氢气体时，可实现高炉减碳34.62%，相比直接喷吹焦炉气，减碳潜力提升17.76%。碳减排主要得益于焦比降低和喷吹气碳质元素减少。高炉气发电也是减碳的关键环节，当喷吹气氢纯度由59.0%提升至97.9%时，该环节碳减排量由9.04%提升至10.85%。通过将焦炉气重整有望突破高炉喷吹富氢气体减碳潜力上限，具有潜在推广价值。

关键词: 模型, 焦炉气, 二氧化碳, 氢, 碳减排