New superstructure-based optimization of property-based industrial water system

Traditional industrial water network only consists of water-using processes and water treatment processes. The practical water-using processes may use freshwater, desalted water, condensation water, steam, circulating cooling water etc. and those are typically water utilities. It is not considered in the up-to-date model of industrial water network. To overcome the limitation, this paper proposed a novel superstructure of property-based industrial water system and it consists of water utility, water-using and water treatment sub-systems. The developed mathematical model includes the relevant equations among different water utilities, flowrate and mass balance constraints and property constraints. The water system of a certain coal-based chemical complex in China is optimized to illustrate the proposed model. The results show that the total annualized cost of the water system is reduced from 1.825 × 108 CNY/y (preliminary design) to 1.494 × 108 CNY/y (optimum design) and the flowrate of water resource is decreased from 1369.855 t/h to 1030.498 t/h.