Chapter 1 - Introduction

Abstract

This chapter provides an overview of various desalination processes, developments, and the needs for industrial desalination. The industrial desalination processes involve the separation of nearly salt free fresh water from sea or brackish water, where the salts are concentrated in the rejected brine stream. The desalination processes can be based on thermal or membrane separation methods. The thermal separation techniques include two main categories; the first is evaporation followed by condensation of the formed water vapor and the second involves freezing followed by melting of the formed water ice crystals. The former process is the most common in desalination and nearly at all cases it is coupled with power generation units, which may be based on steam or gas turbine systems. The evaporation process may take place over a heat transfer area and is termed as boiling or within the liquid bulk and is defined as flashing. The evaporation processes include multistage flash desalination, multiple effect evaporation, single effect vapor compression, humidification-dehumidification, and solar stills. The desalination processes can also be classified according to the type of main energy form of energy used to drive the process.