Simultaneous integration of water and energy on conceptual methodology for both single- and multi-contaminant problems

• It is a new conceptual methodology that is employed to solve multi-contaminant problems.
• A new tool named temperature and concentration order composite curves guides the design of water networks.
• Through this new conceptual methodology, the optimized targets of freshwater and utility are obtained in one step.

This paper proposes a new conceptual methodology for simultaneous integration of water and energy. It is applicable to both single- and multi-contaminant problems with fixed contaminant mass load. The method includes a new graphical approach called as temperature and concentration order composite curves (TCOCC) which is employed to guide the design of appropriate water networks for heat recovery. Based on the obtained water allocation network, the heat is integrated in the system. The optimized targets of freshwater and utility are also obtained in one step. Compared to mathematical programming models in which complex calculations are adopted, our method is relatively simple and is visualized to the design procedure since it is a graphical approach. Furthermore, the temperature parameter is taken into account at the stage designing the initial water networks, which is more beneficial to heat integration. Three literature examples are presented to show the effectivity and advantages of this new method.