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1. University of Benghazi
Faculty of Engineering & Petroleum-Galo
Department of Petroleum Engineering
Prepared by :
Osama A. Alkaseh 1515
Taha A. Benidris 1534
Titl: CRUDE OIL DESALTING

2. INTRODUCTION

3. INTRODUCTION
 Oil desalting is the process of removing water-soluble
salts from an oil stream.
 Chlorides hydrolyzed to hydrochloric acid cause severe
corrosion.
 CaCl2 + H2O → Ca(OH)2 + HCl
 They crystallize and may either remain suspended in the oil
or form scale within the heat-exchange equipment.

4. IMPURITIES
 Most crude oil is produced with some entrained water, which
normally contains :
 chlorides of sodium, calcium, and magnesium.
 sand
 iron oxide
 sulfur
 carbon

5. SCALING IN HEAT EXCHANGER

6. DESALTING PROSSES
 A typical salt specification would be 10 pounds per thousand barrels
(10 PTB).
 The process of desalting will also remove portions of these
solids from the oil.
 Deposition of salts in equipment results in loss on :
1. stream time.
2. reduced production.
3. increased cost from shutdowns.
4. clean-out operations.

7. OPERATING CONDITIONS
A. Level
B. Pressure
C. Temperature
A. Level :
 Operating level of water must be maintained below electrode.
 Conductivity of water cause electric current flow and could shut
down the electric system.
 If level is allowed to raise it will carry over the interface with crude to
the tower causing tower upset and exchangers fouling as well.
 Low level cause carry over of crude with effluent water.

8. OPERATING CONDITIONS
B. Pressure:
 High pressure keeps system from boiling.
 Recommended pressure 50-250psi.
C.Temperature:
■ Decrease in temperature increase the viscosity
making settling of salts and water difficult and vice
versa.
■ Temperate limit is from 90o C to 150oC varying
from crude to crude.

9. Desalting Gives these Benefits
Increased crude throughput
by:
 Running at maximum
capacity
 Less time for
maintenance
Less plugging, scaling of:
 Exchangers
 Furnaces
Less corrosion due to
sulfur, salts and
organic acidity in:
 Exchangers
 Receivers and lines.
Improved products because
of:
 Better operational control
 Less salt and solids in
residual fuel

10. TYPES OF DESALTER
 Natural Desalter
 Chemical Desalter
 Electrostatic Desalter

11. SINGLE-STAGE DESALTING

12. TWO-STAGE DESALTING

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