Targeting of water-using networks involving regeneration with a graphical approach

In this paper, a modified graphical approach is presented for targeting the water-using networks of single contaminant involving regeneration. Two situations are studied in this paper: the regenerated concentration is lower than the lowest limiting inlet concentration (except 0 ppm), and the regenerated concentration is higher than the lowest limiting inlet concentration (except 0 ppm). The latter situation has not been investigated with the graphical methods in the literature. The parameters of the water networks, including Regeneration Pinch, the targets of freshwater, and regenerated water, can be obtained by the proposed graphical approach. Both the Fixed Contaminant Load and Fixed Flow Rate systems are discussed. A few examples are investigated to show the targeting procedure.