A technology-based analysis of the water-energy-emission nexus of China’s steel industry

Steel production is a main water consumer, energy consumer, and a major source of air pollution in China. To mitigate the steel industry’s environmental pressures, the government is promoting several water-saving, energy-saving, and emission-reduction technologies. This study developed a technology-based approach to investigate the water, energy and emission nexus (WEEN) of the steel industry. The results indicate that 4.1m3 of water use and 21.4kWh of electricity use were related with the WEEN per ton of crude steel production in 2014, which accounted for around 66% of the total water use and 7% of electricity consumption of steel production, respectively. Of the WEEN water consumption, 66% and 34% was for cooling and emission control, respectively; 96% of the WEEN electricity consumption was for emission control. The water-energy-SO2 nexus was more intensive in the coking and sintering processes, whereas the water-energy-dust nexus was more intensive in the steel-making process. Diffusion of advanced technology and improved raw material quality can reduce existing SO2 and NOx emissions by 57% and 25%, although at the expense of 5%, 56%, 0.2%, and 40% increases of dust emissions, water consumption, energy consumption, and costs, respectively. Technology sets identified by the Pareto optimization method can reduce the SO2, NOx and dust emissions by 97%, 50%, and 75%, respectively, and water and energy consumption can be reduced by 10% and 2%, respectively; however, costs could increase by 51–74%. This study highlights the need and opportunities for integrating emissions and resource use in nexus studies and production planning.