Essay On Thermal Desalination

CHAPTER 1

INTRODUCTION

In the contemporary world, economic purposes on ships led to the need for a process such as desalination. At the beginning, ships used distillation, in which heat aids in removing salt from water, providing clean water throughout their trips. Later on, thermal desalination started to be used since it was more efficient in providing a continuous supply of fresh water along the sailing.

In 1881, the first desalination mills started to be built in Tigne, Malta and in Jeddah, Saudi Arabia. Following that, membranes started to get involved in desalination and reverse osmosis installations were used primarily to treat brackish water and later seawater after adding improvements to the permeability of the membranes [1].

The reverse osmosis membrane technology has undergone mild advancements and has become the vital selection among other desalination techniques. Reverse osmosis plants correspond to about half the desalination mills (15,000) of the world [1].

The total production capacity of desalination was null between 1945

1) Thermal desalination process

Thermal desalination consists of three major operations; Multi effect distillation (MED), vapor compression (VC), and multi-stage flash distillation (MSF). MSF is the most commonly used method and is still favored in the Middle East.

2) Membrane desalination process

Membrane desalination includes reverse osmosis (RO), nanofiltration, and electrodialysis. Reverse osmosis is the most frequently used membrane process for the desalination of seawater especially in the Mediterranean Sea region [2]. Although thermal desalination has a greater ability to treat highly concentrated saline water with better properties than that of reverse osmosis, RO requires less energy expenditure than thermally based technologies. In fact, RO consumes about 0.4-7 kWh/m3 while thermal desalination needs 35 kWh/m3