Construction and analysis of “water carrier” and “water value” in the iron and steel production

The shortage of water resources has become a huge bottleneck in the development of the iron and steel industry in China. Many studies on water-use by iron and steel enterprises focus only on the volume of water used, however, the water environment and water treatment process of different water qualities are more critical. Therefore, borrowing the concepts of “energy carrier” and “energy value” from the theory of systemic energy-saving, new concepts of “water carrier” and “water value” are introduced to construct the water value model in iron and steel production. Based on the water production or treatment costs for different qualities and volumes of water, consumption of water with different qualities can be converted into consumption of fresh water. Using this conversion method, the water value of the product of each process can be analyzed. Using an iron and steel group in China as a pilot site, the feasibility and applicability of this water value model is evaluated. The results show that the water value of the final product, hot-rolled coil, calculated using this conversion method is 128.94 m3/t. However, the traditional method of analysis, where in calculations are performed using only the volume of water, gives the water value of hot-rolled coil as 194.82 m3/t. The novel method can better reflect the nature of water-use, as compared with the traditional analysis method. In addition, the new method provides novel ways of considering water saving in the steel industry-reducing the water production or treatment costs of different water qualities can also result in water saving.