钢铁行业生命周期碳排放核算及减排潜力评估

Life Cycle Carbon Emission Accounting and Emission Reduction Potential Assessment of Steel Industry

钢铁行业是中国碳密集度最高的工业行业之一,为分析钢铁行业生命周期碳排放及碳减排潜力,从生命周期角度构建碳排放核算模型,以2020年为例开展实证分析,通过优化废钢使用量、化石燃料燃烧量、电力碳足迹因子以及清洁运输比例4项变量,对钢铁行业生命周期碳减排潜力作预测评估,同时使用敏感性分析确定影响钢铁生命周期碳减排因素的关键程度.结果表明,2020年中国钢铁行业全生命周期二氧化碳(CO_(2))排放总量约24.04亿t,其中原料获取和加工生产阶段是钢铁行业碳排放的关键环节,占钢铁行业生命周期CO_(2)排放总量的98%以上.从CO_(2)排放源类别分析,化石燃料节约和外购电力清洁化是钢铁行业降碳的重中之重.到2025年,通过推广低碳技术、优化电力结构、增加废钢炼钢量、提高清洁方式运输比例,分别可使钢铁行业实现20%、6%、5%和1%的碳减排潜力.化石燃料燃烧量对钢铁行业生命周期CO_(2)排放的影响最显著,电力碳足迹因子和废钢炼钢使用量次之.关于钢铁行业节能低碳技术,短期内以推广轧钢工序与高炉炼铁工序低碳技术为主,未来随着电炉炼钢比例逐步增加,以普及电炉炼钢工序低碳技术推动钢铁行业全生命周期碳减排潜力显著提升.

The steel industry is one of the most carbon-intensive industries in China.To analyze the carbon emission and carbon reduction potential of the steel industry in the life cycle,a carbon emission accounting model was built from the perspective of the life cycle.Taking the year 2020 as an example,an empirical analysis was carried out to predict and evaluate the carbon reduction potential of the steel industry in the life cycle by optimizing four variables,namely,scrap usage,fossil fuel combustion,electric power carbon footprint factor,and clean transportation proportion.At the same time,sensitivity analysis was used to determine the key degree of factors affecting carbon emission reduction in the life cycle of steel.The results showed that in 2020,the total life cycle CO_(2) emissions of the steel industry in China was approximately 2.404 billion tons,of which the acquisition and processing of raw materials were the key links in the carbon emissions of the steel industry,accounting for more than 98% of the total life cycle CO_(2) emissions of the steel industry.From the analysis of CO_(2) emission source categories,fossil fuel savings and outsourcing power cleaning were the top priorities of carbon reduction in the steel industry.By 2025,the steel industry could achieve 20%,6%,5%,and 1% carbon emission reduction potential by respectively promoting low-carbon technology,optimizing the power structure,increasing the number of steel scraps,and increasing the proportion of clean transportation.The fossil fuel combustion had the most significant impact on the life cycle CO_(2) emissions of the steel industry,followed by the electric power carbon footprint factor and scrap steelmaking usage.With regard to low-carbon technologies in the steel industry,in the short term,the promotion of low-carbon technologies in the steel rolling process and blast furnace ironmaking process should be the main focus.Later,with the gradual increase in the proportion of electric furnace steelmaking,the promotion of low-carbon technologies in the electric furnace steelmaking process will significantly improve the carbon emission reduction potential of the steel industry throughout its life cycle.