Algorithm of Distillation Plant Parameters Selection Based on “Mass Flow Rate-Enthalpy” Diagram

Abstract

The problem of fresh water lack can be solved my desalination of the seawater. Desalination of the seawater can be accomplished by several methods. Distillation of the seawater is one of the most promising among them. This article deals with algorithm of distillation plant parameters selection based on “mass flow rate-enthalpy” diagram. This diagram allows to estimate operation of the plant by several criteria such as energy efficiency, real distillation plant output, steam compressor and evaporator efficiency. Criterion of optimal coordination of Steam Compressor (SC) and Evaporator-Condenser (EC) characteristics is minimal distance between point which is characteristics of SC and line - characteristics of EC. Diagram shows an example of coordination of two SC with different productivity with characteristics of one EC. Location of these SC characteristics as a points 2a and 2b on the line which is characteristics of EC means perfect example of coordination when potentials of SC and EC productivities are fully utilized. Diagram confirms linear increase of the total energy cost and quadratic increase of the required power of SC if productivity is necessary to increase at constant EC heat exchange area. Besides, considering bended characteristics of EC, it is possible to note higher energy efficiency of distillation plant at higher temperatures Analysis shows that distillation plant with consecutive evaporation of initial water provides optimal value of specific work spent for compression and consecutive connection of stages by steam have the worst value of work spent for compression.