1. VARIOUS PROCESSES FOR REGASIFICATION
LNG TERMINALS
VARIOUS PROCESSES FOR REGASIFICATION

2. What is Regasification? Processes for Regasification of LNG Conclusion
Presentation Frame
Gas Scenario in India
LNG Chain
What is Regasification?
Processes for Regasification of LNG
Conclusion

3. GROWTH OF GAS DEMAND IN INDIA
Large supply deficit
Industry using liquid fuels
LNG import to reduce growing gap
LNG a viable fuel in Indian market
Gas Demand (MMSCMD)
Source: Report of Working Group (XI Plan) of Government of India

4. PROJECTED DEMAND - SUPPLY GAP FOR NATURAL GAS
Demand Supply Gap (MMSCMD)
Years  
DEMAND
179
281
SUPPLIES – DOMESTIC/PIPELINES 71
192
LNG Terminals
Dahej
17.5
Dahej Expansion -
Hazira
10.0
Kochi
Dabhol
Total LNG Imports  87
Total LNG + Domestic Gas
88.5
279
 GAP
90.5 9
Source: Report of Working Group (XI Plan) of Government of India

5. WHAT IS LNG LNG Is Natural Gas Liquefied at –160 oC.
NG is liquefied to make it suitable for transportation in LNG ships through sea routes where transportation of NG by pipeline route is not feasible / economical.
During the Liquefaction process NG is purified to very high level.
LNG is therefore environmentally friendly and efficient fuel.
LNG is subsequently regasified at receiving terminal for use by the End users.
LNG MOVIE

6. Vaporized LNG to Gas Consumers
LNG CHAIN
Gas Field
Liquefaction
Storage
Transfer
Loading
Transportation
(Loaded)
Unloading
Pumping
Regasification
Vaporized LNG to Gas Consumers
Transport
(Ballasted)

7. LNG TERMINAL LNG Vaporizers Metering LP PUMP HP PUMP SHIP LNG TANK
BOG COMP.
Metering
RECONDENSOR
UNLOADING/ VAPOR
RETURN ARMS
LNG Vaporizers LP
PUMP HP
PUMP
SHIP
LNG TANK

8. What is Regasification?
It is the process of converting Liquefied Natural Gas in
Liquid state to Gaseous state by adding heat.

9. Types of Vaporizers Open Rack Vaporizers (ORV)
Submerged Combustion Vaporizers (SCV)
Intermediate Fluid Vaporizers (IFV)
Hydrocarbon Mixture (Rankine Cycle)
Glycol / Methanol Water System
Ambient Air Vaporizers (AAV)

10. Open Rack Vaporizers (ORV)
RLNG
Sea
Water
LNG
To Sea
The term "open rack" is used because the panels
are suspended in a rack, facilitating access
for maintenance.

11. Open Rack Vaporizers (ORV) - Highlights
The construction and operation is very simple.
No control.
high turndown ratio.
reliable considering safety aspects.
capital-intensive.
Environmental issues need to be addressed
High maintenance.

12. Submerged Combustion Vaporizers
Fuel Gas
RLNG
AIR
LNG

13. Submerged Combustion Vaporizers
Highlights
Simple and compact design.
Large load fluctuations.
lower capital cost
Used only where ambient temp. is very low
1.5% fuel consumption
green house effect.
The control is more complicated.

14. Intermediate Fluid Vaporizer with Rankine Cycle

15. Intermediate Fluid Vaporizer with Rankine Cycle
Highlights
It uses the cold heat of LNG for Power generation.
Power Generation is free of any green house effect.
The Capital cost is much higher.
The process is complicated and requires lot of controls.
Large turndown ratio is not possible.
Start-up requires more time.

16. Glycol-Water Intermediate Fluid Vaporizer
RLNG
Air Heater
GW Pump
Water Collection
STV
Water to different users
Water Pump
LNG
Glycol Water Circulation

17. Glycol-Water Intermediate Fluid Vaporizer
Highlights
The capital cost higher than SCV’s but lower than ORV’s.
Minimum operating cost
Simple operation
Most effective where ambient temperature is high
Large Space requirement.
Special Design Consideration
Recirculation of Cold air
Generation of Fog
Removal of condensed water

18. Selection of Vaporizers For Dahej LNG Terminal

19. General Weather Conditions at Dahej
Generally warm & Humid Atmosphere
Average Maximum Temperature 37 deg C
Minimum Temperature 13 deg C
Average Temperature 25 to 30 deg C
Humidity 60 to 90 % (avg. 70%)
Sea Water
High Turbidity
High Copper
High Iron ion concentration

20. SELECTION OF REGASIFICATION SCHEME AT DAHEJ
Open Rack Vaporizers (ORVs) Not Feasible.
Submerged Combustion Vaporizers (SCVs) not desirable.
Advantage of using high ambient temperature.

21. LNG TERMINAL DAHEJ AIR HEATER Metering FUEL GAS STV SCV GW PUMP STV
WATER PUMP
HW / GW EXCHANGER
FOR
BACKUP
BLOWER
BOG COMP.
RECONDENSOR
UNLOADING/ VAPOR
RETURN ARMS
GTG LP
PUMP HP
PUMP
SHIP
LNG TANK

22. AIR HEATERS & STVs –AT DAHEJ
7 STVs / Air Heaters with 112 fans-16.4 MW each
Use of SCVs only if ambient heat is in-sufficient (extreme winter months)

23. Design Issues Recirculation of Cold air Generation of Fog
Removal of condensed water

24. AIR HEATER COMPUTATIONAL ANALYSIS MODEL - ORIGINAL CONCEPT
Detailed investigations were carried out to predict air circulation and to verify the performance of air heaters.
3D calculations were performed simulate air flow behaviour.
It was observed that taking air humidity into account improves air heater performance, due to heat released by condensed vapours.
Simple and efficient means of condensed water removal are required to prevent carry-over of water with the flowing air.
Large amount of condensed water is going to be recovered.

25. AIR HEATER COMPUTATIONAL ANALYSIS MODEL RESULTS - ORIGINAL CONCEPT
We observed that recirculation can occur and led to decrease air heater performance.
Recirculation is mainly caused by confluence of streams comming from parallel units .
The simplest and most efficient solution for minimizing cold air recirculation is to place different unit not parallel to each other.

26. AIR HEATER COMPUTATIONAL ANALYSIS MODEL - REVISED CONCEPT
Detailed investigations were carried out to predict air circulation and to verify the performance of air heaters.
3D calculations were performed simulate air flow behaviour.
It was observed that taking air humidity into account improves air heater performance, due to heat released by condensed vapours.
Simple and efficient means of condensed water removal are required to prevent carry-over of water with the flowing air.
Large amount of condensed water is going to be recovered.

27. AIR HEATER COMPUTATIONAL ANALYSIS MODEL RESULTS - REVISED CONCEPT
Detailed investigations were carried out to predict air circulation and to verify the performance of air heaters.
3D calculations were performed simulate air flow behaviour.
It was observed that taking air humidity into account improves air heater performance, due to heat released by condensed vapours.
Simple and efficient means of condensed water removal are required to prevent carry-over of water with the flowing air.
Large amount of condensed water is going to be recovered.
Ambient Temp 21 deg C
Zero Wind

28. CONCLUSIONS
USE of STVs & Air Heaters offer most economical & Eco friendly regasification scheme for warm & Humid places
Cold Air Re-circulation cannot be avoided but effect can be minimized by Computational Analysis Modeling
Fogging can be considerably reduced by selecting a layout based on the above analysis

29. THANK YOU