Optimization of energy use with CO2 emission reducing in an integrated iron and steel plant

Energy consumption and Carbon emission in iron and steel industry are enormous and need to meet an optimal strategy. Many researches have focused on iron and steel making process (ISMP) in different scales and targets. However, it remains more researches on comprehensive and completed model of ISMP to evaluate the total site energy use and CO2 emission condition. This paper proposed a combined model including long-route iron and steel production with coking, sintering, iron-making, steelmaking and hot-rolling process, and a complex energy network that contains by-product gases, steam and electricity network. The heat balance, mass balance, characteristic curves of devices and chemical compositions of substances in ISMP are introduced as constrains in the model, and the minimum of specific energy consumption (SEC) is set as the optimization objective. The direct CO2 emission (DCE) calculation under optimal energy results is also included. Furthermore, eight cases are designed in this study to evaluate the system, and the optimal parameters of ISMP are obtained. The results show that the optimal total site SEC with total site DCE decreased by 14.07% and 6.65%, respectively, which compared with the original data. The analysis also shows that most of the parameters have a co-efficiency nexus with energy use and CO2 emissions.