An Iterative and Subnetwork-Dividing Method to Design Multi-contaminants Water-using Networks with Multiple Regeneration Units

In the field of chemical engineering, when the regeneration recycling process is introduced into the water-using networks (WUNs), several parameters that affect the cost of WUN can be reduced: the consumptions of freshwater and the regenerated water, and the wastewater discharge. However, it is often difficult to design the WUNs involving regeneration recycling and multiple regeneration units. This article introduced a subnetwork-dividing method to design WUNs involving regeneration recycling and multiple regeneration units. This method minimizes the consumption of freshwater and reduces the consumption of regenerated water. The main steps of the proposed method include: dividing of the whole network as pre-regeneration subnetwork and regeneration subnetwork, and design of subnetworks to obtain the final results. The results of a literature example: the consumption of freshwater is 58 t/h and the consumption of regenerated water is 179.143 t/h, it can be seen that method proposed in this paper is simple and effective. The design results obtained by this work are comparable to that obtained in the literatures.