Multi-energy optimization under the water-energy-carbon nexus in a typical iron and steel plant

The multi-energy system in iron and steel plants has strong coupling characteristic, which makes the energy distribution complex and difficult in energy management. Additionally, the steel works is a manufacture process with high-carbon emissions, and it is vital to assess the environmental stress from the sights of nexus between energy, water and carbon emission. In this study, a multi-energy and multi-objective mixed integer non-linear programming (MINLP) model is established to optimize the energy system under the water-energy-carbon nexus in iron and steel plant. And the multi-energy is considered the couple of gas-steam-electricity. The multi-objective functions include the economic performance, the CO2 emissions, the water generation, and the global energy efficiency. Due to the contradictory of the objective functions, the utopia tracking approach is used to normalize and assess the functions. To fit the actual situation of the equipment, this paper made a fitting curve for the energy efficiency of the equipment. The minimum economic operation cost results show that the studied iron and steel plant has great potential in reducing economic cost (7.6 %), emission mitigation (4.7 %), system water production improvement (807 t) and global energy efficiency (54.48 %). Besides, the research will help the iron and steel plant to reach the carbon peak and carbon neutrality target.