Evaluation of symbiotic technology-based energy conservation and emission reduction benefits in iron and steel industry: Case study of Henan, China

Iron and steel industry (ISI) has been facing great pressure of energy conservation and emission reduction (ECER), and industrial symbiosis (IS) is expected to be a promising path to realize ECER in ISI. This study systematically identified the material and energy flows in ISI by using material flow analysis method to collect symbiotic technology at first. Then, a comprehensive assessment framework based on life cycle assessment and conservation supply curve was established to quantify and screen symbiotic technologies. On this basis, the ECER potential brought by promoting the selected technologies to Henan ISI was evaluated by scenario analysis. The result shows that: (1) The collected 35 technologies have remarkable effects on reducing the environmental impacts of Human Toxicity Potential, Primary Energy Demand and Global Warming Potential. And 18 best available technologies were selected after the comprehensive assessment. (2) The promotion of the best available technologies could bring great ECER potential to Henan's ISI, with energy saving of 1.24 Mtce, emission reduction for CO2 of 4.64 Mt, SO2 of 6.97 kt, NOx of 4.00 kt and PM of 2.16 kt to Henan's ISI in 2030 comparing with 2017, and the ECER rate reached 9%, 13%, 26%, 7% and 3.5% respectively. (3) Coking, ironmaking and steelmaking processes contributed the most to the ECER potential, while energy exchange technologies of generating electricity using sensible heat of coke (E1), recycling sensible heat from coke oven exhaust gas (E2), generating electricity from saturated converter steam (E12), and material substitution technologies of blast furnace slag instead of cement doping to produce concrete (MS7), and steel slag instead of cement doping to produce concrete (MS10) had significant ECER effect. In addition, targeted policy recommendations were proposed for the promotion of symbiotic technology in ISI. This study is helpful to improve the method of evaluating symbiotic technology at technical level, enrich the research of IS at industry level, and provide reference for the follow-up study in IS field.