Investigation of the residual heat recovery and carbon emission mitigation potential in a Chinese steelmaking plant : A hybrid material/energy flow analysis case study

As an energy intensive industry, China's iron/steel industry faces the challenge of energy conservation and carbon emission reduction. Energy efficiency, especially residual heat recovery is a critical issue. China is promoting a circular economy strategy in the iron/steel industry, technology upgrading and industrial symbiosis make the material and energy flows more complicated. In order to quantify the energy flows and the related residual heat recovery and carbon emission mitigation potential, this study proposes a hybrid material and energy flow analysis approach at company level. We analyze the material based energy flow routes and the transformation rules. Then, we develop an evaluation index to evaluate the specific energy consumption (SEC) and direct carbon dioxide (CO₂) emissions (DCE). Furthermore, a case study is conducted in a 10 million ton/year steelmaking plant in northern China. Results verified the effectiveness of the proposed approach. According to the results, the residual heat and carbon emission is mapped out graphically. Results highlight that the case company has 4.87GJ/tons of crude steel residual heat recovery potential, equal to 26.08% of the total energy consumption. Finally, policy implications on the ever-improvement of residual heat utilization and the future research concerns are proposed and discussed.