Synthesis of heat-integrated water-using networks in process plants

This paper presents a general mathematical model to synthesize heat-integrated water-using networks that potentially lead to significant water and energy savings. The formulation is based on superstructures of water-using (WUN) and heat exchanger networks (HEN) for all possible flow connections and stream matches. The superstructure of WUN consists of schematic diagrams for water-using units, regeneration units, and buffer tanks, while the superstructure of HEN is a stage-wise representation. In particular, a set of constraints are incorporated in the model for the automatic identification of hot and cold streams from a water system. An example is used to illustrate the proposed approach, where the elimination of regeneration recycling will be also considered.