钢铁企业能源消耗与CO_2减排关系

Relationship between the energy consumption and CO_2 emission reduction of iron and steel plants

建立了钢铁企业长流程CO2过程排放模型,给出总排放和工序排放的计算方法.计算发现:国内某800万t产量规模的典型钢铁企业CO2总排放在2007年达到1561.64万t,吨钢排放1.85t CO2;工序排放从大到小依次为炼铁、焦化、烧结、轧钢、炼钢、熔剂焙烧和球团工序,其中炼铁和焦化工序排放分别占总排放的58.83%和11.25%.为了评价钢铁企业能源消耗和CO2减排关系,提出钢铁企业CO2综合排放因子和能耗碳饱和指数评价方法.研究表明,为了减少CO2排放,钢铁企业不仅需要降低总体能耗,还需要降低能耗的碳饱和指数,能耗碳饱和指数与能源结构相关,能源结构中CO2总影响系数大的能源种类消耗量越大(例如焦炭),碳饱和指数越高,越不利于CO2的减排.这说明实现钢铁生产的生态园区化、优化能源结构以及加强钢铁生产的能源转换功能对钢铁企业减排有显著作用.

A CO2 process emission model was buih to calculate the CO2 emission of iron and steel plants for total and each process. The total emission of a specific plant with the productivity of about 8 million tons per year is 15.61 million tons and the emission intensity is 1.85 t CO2 for per ton of steel. Calculation results show that the order from the highest emission to the lowest one is BF, coking, sintering, rolling, BOF, flux roasting, and pelletizing process; the BF process and coking process account for 58.83% and 11.25% of the total emission, respectively. The general emission factor （GEF） and carbon saturation index （CSI） were proposed to evaluate the relationship between energy consumption and CO2 emissions in iron and steel making. It is found that the reduction of CO2 emissions results from not only energy saving but also the CSI reduction; the CSI has a significant relationship with the energy structure, and the higher percentage of energy with a higher total CO2 impact coefficient in the energy structure （ coke for example） will results in a higher CSI, which has negative effect on the reduction of CO2 emissions. Developing eco-industrial parks, optimizing the energy structure, and enhancing the energy transform function of iron and steel making all have significant benefit on the reduction of CO2 emissions.