Process industries need to efficiently utilize energy and water for the reduction in the operating cost as well as to contribute towards achieving sustainability. The heat integrated water regeneration network (HIWRN) reduces the energy and water requirements together. Typically, HIWRN is optimized by maximizing heat exchange between processes including the regeneration unit that operates at a predetermined temperature. A superstructure based (non-)-linear programming framework has been proposed to synthesize a HIWRN. In literature, regeneration flow rate and contaminant concentration were optimized along with energy and water, but the temperature of regeneration unit was considered as a constant. This paper focuses on the simultaneous optimization of energy and water consumption in HIWRN by varying the regeneration temperature as well. The effect of varying the regeneration temperature on the water and energy consumption and consequently on the operating cost is discussed with the help of an illustrative example. The proposed methodology minimizes the operating cost by reducing energy and water requirement simultaneously and thereby improves the overall sustainability.
