1. Lecture (12): Water Desalination

2. Lecture (12): Water Desalination
Lecture (12): Lecture objectives:
By the end of this lecture students should be able to:
To know the description of desalination stages.
To know the desalination technologies classification
To know desalination plants in KSA.

3. Introduction
Many regions in the world do not have easy access to fresh drinking water
Desalination process helps remove salts from sea water to make it drinkable
Pros: Brings drinking water to many dry regions
Cons: Expensive
In some parts of Middle East, a liter of water is more expensive than a liter of gasoline

4. Description of desalination stages

5. Desalination technologies classification based on the separation process adopted

6. Desalination technologies classification based on the type of energy used

7. PROCEDURES Reverse Osmosis Distillation Electro dialysis
Multistage flash (MSF)
Multiple effect distillation (MED)
Vapor compression
Electro dialysis
Vacuum freezing

8. Reverse Osmosis Water pressure increased
Pumped through permeable membranes
Salts separated from water due to membranes
Most desalination plants utilize this technology

9. Multi Stage flash Steam is used to heat tubes of saline water
Heated water flows into “stages” that are at lower pressure
Water boils rapidly and “flashes” into steam

10. Installed Capacity (m3/day)
Existing Plants
Type of
Technology
Installed Capacity MW
Installed Capacity (m3/day)
Year of Commission
Plant Name
Location #
Single Purpose (MED) -
9,000
2009
Alwajih (3)
Alwajih 1
Single Purpose (MSF) 11
22,886
1986
Khafji (2)
Khafji 2
Single Purpose (RO)
4,400
Umlujj (2)
Umlujj 3
Umlujj (3) 4
Farasan (2)
Farasan 5
18,000
Rabigh (2)
Rabigh 6
1989
Duba (3)
Duba 7
2,270
1983
ALBirk 8
4,500
1987
ALAzizih 9
1990
Haql 10
2008
ALQunfutha
ALlith 12
Dual Purpose (MSF)
710
223,000
Khobar (2)
Khobar 13
479
280,000
2000
Khobar (3) 14

11. Installed Capacity (m3/day)
Existing Plants
Type of
Technology
Installed Capacity MW
Installed Capacity (m3/day)
Year of Commission
Plant Name
Location #
Dual Purpose (MSF)
360
137,729
1982
Jubail (1)
Jubail 15
1225
947,890
1983
Jubail (2) 16
Single Purpose (RO) -
90,909
2000
Jubail (RO) 17
357
108,074
1981
Yanbu (1)
Yanbu 18
150
144,000
1998
Yanbu (2) 19
128,182
Yanbu (RO) 20
256
88,357
1979
Jeddah (3)
Jeddah 21
590
221,575
Jeddah (4) 22
56,800
1989
Jeddah (RO1) 23
1994
Jeddah (RO2) 24
240,000
2013
Jeddah (RO3) 25
263
223,000
Shoaiba (1)
Shoaiba 26
520
454,545
2001
Shoaiba (2) 27
108
97,014
Shoqaiq 28

12. Water Demand in KSA – Main Figures 2010 2025
Population
(Million)
27.2
34 (*)
Water demand
(Million m3/day)
6.8
8.5 (*)
Desalination share in water
53%
(3.3 Million m3/day)
63%
(5.2 Million m3/day)
(*): assuming an average annual growth rate of 1.5%

14. Multi Stage flash (cont…)
Generally, only a small amount converts to steam since rapid vaporization results in cooling of water
Thus water is flashed multiple times in different stages at lower pressures, requiring no extra heat
But, multi stage flashing reduces thermal efficiency
85% of world’s desalinated water is generated through MSF
Recently the equipment has become cheaper

15. Shoaiba Desalination Plant
Largest desalination plant in the world
Produces 450,000 m³/day
Per year
150 million m³ of water is
desalinated
Total cost is $1.06 billion
To increase the thermal efficiency of this plant, the maximum number of stages is set to 25 (MSF)
Research in the field is resulting in more plants coming up in Florida and California

16. Reverse Osmosis https://www.youtube.com/watch?v=mZ7bgkFgqJQ