water desalination - Saudi Arabian Water Environment Association

37 Pages·2005·1.88 MB·English

by  Jimmy Alde

WATER DESALINATION
BY
MOHAMMAD AK. AL-SOFI
ARABIAN CONSULTING ENGINEERING CENTRE
POST OFFICE BOX 3790, AL-KHOBAR 31952,
KINGDOM OF SAUDI ARABIA
E-mail: [email protected]
1 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
Mankind’s knowledge did not stop
at appreciating the secrets of water
but merged in his endeavors to
imitate what happens in nature.
Late Professor (of Desalination)
Robert Silver once said that,
“Earth is the largest distillation
unit”.
2 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
B A = APEX
SEA WATER
SAND BASIN
B1
A1
FRESH WATER
3 AN ANCIENT SAMAWAR
EARTH 2 AL-GHUMSAH 3RD MILLENNIUM B.C.
1
A1 = 2A
B1 = 0.5B
DISTILLATION ABOARD
4 DOUBLE WALLED WATER 5 SHIPS 2ND MILLENNIUM B.C. ARISTOLS CITATION
6
CAVERN 3RD MILLENNIUM B.C.
1ST MILLENNIUM B.C.
3 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
7 THE HOLLOW WAX BALL 8 THE OLDEST ANCESTOR OF 9 PERFUM DISTILLATION
1ST MILLENNIUM A.D. DAULL PRODUCTION OF HERIO OF ARABIAN CIVILIZATION
1ST MILLENNIUM A.D. 1ST MILLENNIUM A.D.
10DESALINATION USING
DAMASQUAIN GLASS 11LEONARDO D’VINCI CITATION 12 THE TALE OF DANIEL
2ND MILLENNIUM A.D. 2ND MILLENNIUM A.D. DAVO
2ND MILLENNIUM A.D.
4 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
Today the Arab World desalinates more water than all
other parts of the globe combined. Saudi Arabia by
itself represents about one-fourth of the total world’s
capacity. Petroleum wealth has been the prime force
behind this paramount growth in desalination capacity
in more than one way. Oil booms have led to
escalating rises in demand, the oil wealth provided
capital funding for this growth and above all energy
availability supported such high production rates of
desalinated water. Some of the highest per capita
desalination production rates are in Qatar and United
Arab Emirates (UAE).
5 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
(a)
(b)
(c)
Multiples
% %
20 100 7
19.71 6.9
90 95.2
6
80
15
5
70 TTTHHHIIIRRRSSSTTTYYY
COUNTRIES
NNNAAATTTIIIOOONNNSS
WATER 60 WITH
4
RICH SUSTAINABLE WHAT TO DO?
10
50
COUNTRIES WATER 1. Allot, e.g.:
3
40 RESOURCES i) Management
ii) Tariff Structure &
30
2
5
iiiiii)) TTEECCHHNNOOLLOOGGYY
20 23.5
1
1.11
10
0.48
0
0 0
Norway Japan
Syria Egypt Iraq Saudi Arabia
Consumption Divided by Renewable Water Resources
NOTE: Surface water would also provide renewable electricity.
6 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
Desalination Processes
As known today: 1a-3a, or as could be thought of: 3b
Desalination processes can be divided into:
1. Physical processes of phase change:
a. Solar distillation, stands b. Multi-stage flash
half-way between (MSF) distillation
nature & MSF.
c. Multi-effect distillation d. Vapor-compression
(MED) distillation (VCD)
REHEAT
e. Pervapouration* f. Freezing
* A process of vaporization and vapour permeation.
7 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
Desalination Processes (Cont’d.)
2. Physical processes of ionic change:
a. Reverse b. Electrodialysis
Osmosis (RO) (ED)
c. Inoexchange d. Hydration
e. Electromagnetic f. Chelation
3. Processes of chemical change:
a. Precipitation b. Bio-Desalination
8 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
Performance of MED/TVC is Highly Influenced by Scale
Formation
9 H20 Desalination
Nov. 21, 2005
WATER DESALINATION
Salient Features of MED
(cid:190) High heat transfer rate (thin film boiling and condensation).
(cid:190) Maximum temperature operation 65 °C to limit scale formation.
(cid:190) Higher frequency of acid cleaning. Tube configuration is not
suitable for sponge ball cleaning.
(cid:190) Higher Gain output (GOR)*a
MED GOR = N-1
(cid:190) MSF GOR = N/2
(cid:190) Low power consumption* (2 kWh/m3)a
(cid:190) Small to medium capacity size plants* in MIGD range of:
0 1 2 3 4 5 6b 7 8b
* These numbers are based on:
a) Different steam grade than that required by MSF thus: GOR & Power Consumption
are fictitious references, as they are used by many; yet the use of PR will give more
realistic references.
b) Unit capacities of over three are achieved by duplicate(s) of parallel ejectors and
distillation stages.
10 H20 Desalination
Nov. 21, 2005