A new energy analysis model of seawater desalination based on thermodynamics

Abstract

Seawater desalination is an energy-intensive process and many efforts have been made to reduce energy-consumption of desalination process. In this study, a new energy analysis model of seawater desalination based on thermodynamics is proposed. The minimum energy consumption of ideal desalination process is calculated out by subtracting the Gibbs free energy of seawater form the Gibbs free energy of freshwater. The results show that the minimum energy consumption for the ideal desalination process decreases with the increase of the salinity of freshwater, and increases with increase of the salinity of seawater and operation temperature. Compared the minimum energy consumption with the average energy consumption of plans in industry, there are much irreversible loss in the actual desalination process. For a given feed water quality and a given freshwater quality standard, the efforts should be made to invent new desalination technologies which can operate under low temperature condition.