A heuristic design procedure for water‐using networks with multiple contaminants

Abstract

in Wiley InterScience (www.interscience.wiley.com).On the analogy of the water-using networks with single contaminant, we will introduce new methodology concepts: the concentration potentials of the demand streams and those of the source streams in the water-using systems with multiple contaminants, based on the overall allocation possibility of the source streams to the demand streams. In the design procedure, the performing order of the processes is determined by the inlet concentration potentials of the processes. The processes with the lowest inlet concentration potential will be performed first. When satisfying the inlet stream of the process being performed, the source with the largest quasi-allocation amount, which is defined in this article, will be used first. A few literature examples are investigated to show the method proposed. The results show that the method proposed in this work is very simple and the freshwater consumptions of the designs obtained are very close to the minimum freshwater targets.

An iterative method for design of water‐using networks with regeneration recycling

“…It should be pointed out that, in the work of Liu et al, 23 i=j was taken as a limiting condition for the CPD and CPS because recycling was not considered. In this article, the condition i=j is not needed any more because regeneration recycling is considered.…”

“…For example, for the two streams with contaminants A, B and C, S 1 ¼ (40, 60, 20) ppm and S 2 ¼ (30, 40, 70) ppm, it is difficult to tell if the concentrations of S 1 are lower than those of S 2 or not, because the concentrations of contaminants A and B in S 1 are higher than those in S 2 , but the concentration of contaminant C in S 1 is lower than that in S 2 . To determine the concentration order of the streams in a water-using system of multiple contaminants, Liu et al 23 introduced the concepts of the concentration potentials of the demand (inlet) streams (CPDs) and that of the source (outlet) streams (CPSs).…”

“…The design of the network involving regeneration reuse/recycling can be obtained by using the design method proposed for the network involving reuse only (for example, the method of Liu et al 23 ). However, the flowrate and concentration(s) of the regenerated stream are unknown before detailed design.…”

“…The regenerated stream will be formed by the sources which meet the following conditions: (a) not reused by the demands in the design, (b) with high reuse-possibility after regeneration, as will be discussed later. In this article, we use a modified design procedure of Liu et al, 23 which is based on new concepts, the concentration potentials of demands and sources, to design the water networks. When the differences of the regenerated concentrations for the two adjacent iterations are in the allowable range e (0.1 ppm in this article), the iteration can be finished.…”

“…By designing of the subnetwork before regeneration, the flowrate and concentration(s) of the regenerated stream were obtained. Then including the regenerated stream in the sources of the network with reuse only to form the network involving regeneration reuse, the design of the networks involving regeneration reuse was obtained by using the method proposed for the networks involving reuse only (Liu et al 23 ). However, Liu et al 22 did not consider the problem about regeneration recycling.…”