Economic Analysis Of The Dual-purpose Plant Desalination System

With the accelerating economic growth, the environmental pollution problem increasing serious, The lack of fresh water resources become an important question. It affect the world economic development and ecological environment. Global reserves of seawater about1.37billion km3,95.3%can be used by human production and life. Desalination of seawater is an effective way to solve the shortage of freshwater resources.Huge energy demand control the water cost of the desalination plant, that made the seawater desalination technology can not effective application. Dual-purpose plant effectively reduce the energy costs of desalination. How to accurately calculate the water cost is very important for evaluation the thermal efficiency of dual-purpose plant.This article in view of the dual-purpose plant using two different seawater desalination technology about multi-stage flash (MSF) and multi-effect distillation(MED) dual-purpose plant, using the method of heat, the actual enthalpy drop method, the exergy analysis, and reference cycle method and simplified exergy algorithm to calculated the cost of water, and compares the advantages and disadvantages of five kinds of water and power energy allocation method Compared the thermal economy of two different water desalination technology dual-purpose plant, analysis of the two unit exergy loss of each device, Analysis of the entire unit cycle thermal efficiency change after steam extraction to seawater desalination.This study have guiding significance for operation and optimization of dual-purpose plant.