Optimization of Water Systems with the Consideration of Pressure Drop and Pumping

Abstract

Novel automated design method has been developed to consider impacts of pressure drop and pumping arrangement in the water network in which water reuse is exploited to reduce freshwater consumption in process industries. A superstructure-based optimization framework has been developed to systematically consider all the key design issues simultaneously, including flow rate constraints, pressure-drop constraints, and other operational constraints, as well as to fully accommodate rigorous economic trade-off between freshwater cost, piping cost, and pumping cost. The proposed optimization study enables the identification of the optimal distribution of water within the network, together with the most appropriate location and capacity of pumps required for water systems. A robust and reliable solution strategy has been developed to effectively deal with computational difficulties associated with solving a mixed-integer nonlinear programming problem, with the aid of the effective application of physical insights gained from conceptual understanding of the design problem. The network complexity has been readily controlled by imposing design constraints in the optimization. Examples have been provided to prove the effectiveness of the design method developed in this paper and to demonstrate the importance of considering pressure drop constraints in practice.