Natural gas processing technology refrigeration

1. Mohamed Abdelraof Saad
LPG
Liquefied Petroleum
Gas

2. Mohamed Abdelraof Saad
Handling LPG

3. Mohamed Abdelraof Saad
Methods used for chilling natural gas
Refrigeration:
• This method uses an external refrigeration system to chill the gas stream. Typical
refrigeration systems use either propane or Freon as the refrigerant.
Pressure Reduction:
• With this method the pressure of the gas stream is reduced with a pressure reducing valve
called a J-T valve. The reduction in pressure causes a reduction in temperature.
Expansion:
• Gas at a given temperature and pressure contains energy which is in the form of heat,
pressure or velocity.
• Expansion method utilizes this energy. In this method the gas stream passes through an
expander-compressor.
• As gas flows into the expander side of the expander-compressor, the pressure drops.
• The flowing gas also turns a wheel in the expander.
• Energy to turn the wheel is removed from the inlet gas and is transferred to the outlet gas
being compressed in the compressor. The combination of gas expansion and removal of
energy produces very low (cryogenic) gas temperatures.

4. Mohamed Abdelraof Saad
Methods used for chilling natural gas
Method Typical Percent Recovery
Refrigeration 0º to – 20ºF
(–18º to – 29ºC)
Ethane 25
Propane 55
Butanes 93
Heavier 97
Pressure Reduction
(J-T Process)
– 50º to – 70ºF
(– 46º to – 57ºC)
Ethane 70
Propane 80
Butanes 97
Heavier 99
Expander Process –125º to – 150ºF
(– 87º to – 101ºC)
Ethane 80
Propane 96
Butanes 99
Heavier 100

5. Mohamed Abdelraof Saad
Refrigeration
• Refrigeration cools the
natural gas stream by
passing the stream
through a chiller.
Chilling causes the
heavier hydrocarbons
to liquefy and these
can then be separated
from the gas Propane liquid

6. Mohamed Abdelraof Saad
Cryogenics
• Cryogenics can
separate and recover
similar quantities of
propane and heavier
hydrocarbons as lean oil
absorption.
• However, cryogenics,
unlike the other
methods, can recover
very high quantities of
ethane (80 – 95 %).

7. Mohamed Abdelraof Saad
Refrigeration .
Refrigeration, by definition, is
the process of moving heat
from one temperature level
to a higher temperature
level.

8. Mohamed Abdelraof Saad
Typical LPG
F-1
F-2
D-1
A
D-1
B
D-1
C
H-1
V-1
A-1
C-4
FEED
GAS
E-1
E-6
E-4
E-3
E-2
E-8
C-1
V-3
C-2
V-4
V-5
T-1
V-6
V-9
T-2
R-1
E-5
E-6
V-10
P-2
P-3
R-2
A-3
E-7
A-4
ST-1/2/3/4
V-13
V-12
C-3
Enterm.
Feed Gas
LPG to
Pumping
Cond. to
Pumping
GSales
as

9. Mohamed Abdelraof Saad
TURBOEXPANSION

10. Mohamed Abdelraof Saad

11. Mohamed Abdelraof Saad

12. Mohamed Abdelraof Saad
Cooling by Expansion or
External Refrigeration

13. Mohamed Abdelraof Saad
Refrigerated lean oil
absorption process

14. Mohamed Abdelraof Saad
conventional
turboexpander process

15. Mohamed Abdelraof Saad
Storage , Loading and
Chemical injection .
•Spherical tanks used to
minimize force against the
tank wall .
Mercaptan injected into
LPG loading line as an
odorant