Abstract
The iron and steel industry has abundant heat resources, but the recovery rate of waste heat is quite low. In this aspect, thermal energy storage technology offers a promising approach for the recovery of massive and intermittent waste heat, which is important for energy saving and emission reduction, as well as a crucial way to realize carbon peak and carbon neutrality. In this study, an overview of the distribution and characteristics of waste heat resources in steel industry is provided firstly. Then the potential of integrating molten salt thermal energy storage to production processes such as iron ore sintering, steelmaking and by-product gas power generation in steel mills is presented. Waste heat of hot sinter, converter flue gas and exhaust gas of the combusted by-product gas in boiler is recovered by molten salt and stored in two tanks. Finally, taking a steel plant in China as an example, we investigated the molten salt thermal storage system design for an idle 20MW by-product gas combustion boiler from technical and economic viewpoints. The results show that molten-salt thermal energy storage could not only decrease the bleeding rate of blast furnace gas, but also realize the peak-shaving of power load and economic savings.
