CHAPTER TEN - Optimization of seawater desalination systems

Abstract

Optimization is a powerful tool through which one or more chosen quantities, known as objective functions, can be minimized or maximized to determine optimal values of design parameters. In recent years, the development and growth of the desalination industry has been highly dependent on the optimization of systems, processes, and designs. Optimization can help efforts aimed at improving freshwater quality and system efficiency, as well as reducing specific energy consumption, cost, and environmental impact. This chapter presents a structure for optimization of stand-alone or combined desalination systems operating with renewable energy resources to determine the optimum design parameters for each component based on the objective functions considered. To formulate an appropriate optimization approach for desalination plants, the following questions should be addressed: (1) What equipment/processes should be selected for a desalination process? (2) How should the components/parts be arranged for the best outcome? (3) What are the best characteristics (e.g., capacity, size, cost) for the components/parts? (4) What are the best values of process parameters (e.g., pressure, temperature, composition, flow rate) for each stream interacting with the desalination system? To answer these questions, optimization elements need to be defined, including optimization criteria, system boundaries, objective functions, and decision variables. In this chapter, various optimization methods are described, and a step-by-step procedure for the optimization of renewable energy–based desalination systems is presented and discussed. Also, several case studies are provided to show how optimization algorithms can be applied to desalination systems that use one or more renewable energy resources.