Received: 21 December 2019 Accepted: 04 February 2020 Published: 01 March 2020
In this paper, simultaneous management of energy and water systems in single contaminant state was considered in two different conditions: (i) systems with only fresh water usage and (ii) systems with maximum reuse of water. In first mode, situations of individual stream, isothermal stream and non-isothermal stream mixing were investigated. Graphical and conceptual techniques for minimizing the targets have been used. As a case study, the water minimization along with energy-efficient in gas refinery was considered. Fresh water consumption of the refinery is 34 kg/s. Using non-isothermal mixing, number of streams and heat exchangers were decreased, but energy targets were increased. Fresh water consumption of final water network was reduced to 21 kg/s because the Cooling tower as a major water-using operation unit didn’t use fresh water anymore and a single contaminant approach was considered too. The new water network has 1399.2 kW hot utility duty and 962.2 kW cold utility duty.