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

A CO2 process emission model was built 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 1.85t 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.