Desalination, 2nd Edition

Chapter 2Thermal Desalination Processes

Joachim Gebel

Department of Technology and Bionics at the Hochschule Rhein-Waal, Kleve, Germany

Abstract

This chapter starts with an extract of fundamentals of engineering science such as thermodynamics and heat transfer. Building on this, mass- and energy balances for single-effect and multiple-effect distillation processes are introduced. A complete set of design equations for MED, MSF and mechanically as well as thermally driven vapor compression plants is presented. In order to be able to compare the different processes in terms of energy demand, the so-called Gained Output Ratio as a performance indicator is introduced and discussed. Based on a vivid description of history of thermal seawater desalination, future prospects and challenges for thermal desalination technologies are discussed at the end of the chapter.

Keywords: Mass- and Energy Balances, Single-Stage Evaporation, Multiple-Effect Distillation (MED), Multi-Stage-Flash - Evaporation (MSF), Multiple-Effect Distillation with Thermally Driven Vapour Compression (TVC), Single-Stage Evaporation with Mechanically Driven Vapour Compression (MVC), Gained Output Ratio (GOR), Performance Ratio, Primary Energy Consumption, Historical Review

2.1 Introduction

Desalination of seawater or brackish water is achieved by several desalination techniques out of which we are going to discuss desalination using thermal energy, i.e. heat, within the frame of this chapter. First, the following ...