14th INTERNATIONAL CONFERENCE

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14th INTERNATIONAL CONFERENCE EXHIBITION ON
LIQUEFIED NATURAL GAS
LNG The growing alternative
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SONATRACH / ACTIVITE AVAL
IMPROVEMENT OF HIGH HEATING VALUE OF LNG BY
OPTIMISING THE LPG EXTRACTION
Abdelouahab MADOURI PROCESS ENGINEER GL1Z PLANT
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• SUMMARY
• INTRODUCTION
• PREVIOUS OPERATING DIFFICULTIES
• SCRUB TOWER SYSTEM MODIFICATION
• RESULTING PROBLEMS
• OPTIMISATION OF LPG EXTRACTION
• CONCLUSION

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INTRODUCTION
FIRST BASE-LOAD LNG PLANT
CAMEL PLANT AT ARZEW, ALGERIA
STARTING PRODUCTION IN 1964
MAKING ALGERIA THE PIONEER OF LNG PLANT
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INTRODUCTION

• LNG-1 PLANT
• Plant Construction Beginning of 1970s
• Production Start up February 1978
• Plant Capacity 9 mtpy
• Number of Trains 6 Parallel Trains
• Liquefaction Process Propane-MCR
• LNG Storage Capacity 300 000m3

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INTRODUCTION
LNG-1 PLANT PROCESS MAIN UNITS
FRACTIONATION
PRETREATEMENT
HEAVY HYDROCARBON SEPARATION
ACID GAS REMOVAL
DEHYDRATION
LIQUEFACTION
NG FEED
LNG SHIPPING
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FEED CHILLING AND SEPARATION SYSTEM
Propane Condenser
Reinjection Products from Fractionation
- 34C
- 34C
Feed to Main Exchanger
Propane Chillers
Scrub Tower Separator
Feed from Dryers
Reboiler
Reflux pump
to Fractionation
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PREVIOUS OPERATING DIFFICULTIES
FEED QUALITY
ORIGINALLY
CURRENTLY
HEAVY
LEAN
LONG START UP TIME
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PREVIOUS OPERATING DIFFICULTIES
LONG START UP TIME
PRODUCTION LOSS
GAS FLARING
INCREASE ANNUAL AUTOCONSUMPTION
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PREVIOUS OPERATING DIFFICULTIES
MAIN FACTORS
INSUFFICIENT RECYCLE PRODUCT
INSUFFICIENT PROPANE REFRIGERANT
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SCRUB TOWER SYSTEM MODIFICATION
ADDITION OF LPG RECOVERY HEAT EXCHANGER
INCREASE LPG EXTRACTION
REDUCE START UP TIME MEET LNG PRODUCT
SPECIFICATION
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LPG EXTRACTION INCREASED
Reflux
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SCRUB TOWER SYSTEM MODIFICATION
BENEFITS
REDUCTION OF START UP TIME
ELIMINATION OF RECYCLE NEED
(ON NORMAL OPERATION)
MINIMISING PRODUCTION LOSSES
DECREASING GAS FLARING
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RESULTING PROBLEMS
NEW PROBLEMS
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RESULTING PROBLEMS
DECREASE OF HIGH HEATING VALUE
LOW COOLING TEMPERATURE
LPG EXTRACTION INCREASE
REDUCING HEAVY COMPONENTS IN FEED STREAM OF
CRYOGENIC HEAT EXCHANGER
DECREASE OF LNG PRODUCT HHV
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OPTIMISATION OF LPG EXTRACTION
SATISFYING LNG QUALITY
OPERATING TEMPERATURE ADJUSTMENT
DESIGN TEMPERATURE REVIEW
FIELD RUN TEST
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OPTIMISATION OF LPG EXTRACTION
TEST OBJECTIVES

• IMPROVE LNG HIGH HEATING VALUE

• ELIMINATE FRACTIONATION DISTURBANCES

• ELIMINATE ETHANE BUTANE REINJECTION

• MEET ETHANE SPECIFICATION

• AVOID PLUGGING PROBLEMS

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OPTIMISATION OF LPG EXTRACTION

• TEST PROCEDURE
• KEEP CONSTANT FEED TEMPERATURE
• RAISE COOLING TEMPERATURE
• CUT OFF ETHANE BUTANE REINJECTION
• MAINTAIN PROPANE REINJECTION
• MAINTAIN RECYCLE PRODUCT

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OPTIMISATION OF LPG EXTRACTION
TEST FOLLOW UP
MONITORING (LABORATORY ANALYSIS)
SCRUB TOWER OVERHEAD SPECIFICATION
LNG PRODUCT COMPOSITION
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OPTIMISATION OF LPG EXTRACTION
TEST RESULTS
- 41 C TO - 40C
IMPROVEMENT OF LNG PRODUCT HHV
OPTIMISATION OF LPG EXTRACTION
DESIRED LNG SPECIFICATION
REQUIRED REFLUX RATE
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OPTIMISATION OF LPG EXTRACTION
10.500
10.511
10.450
10.475
HHV (thermies/Nm3)
10.400
DESIRED HHV
10.401
10.390
10.350
10.369
10.341
10.300
HHV increase with the increase of cooling
temperature
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OPTIMISATION OF LPG EXTRACTION
9.2
Maximal specified limit 8.5 mol
8.79
8.4
8.58
Ethane content (mol)
8.14
8.10
7.69
OFF SPECIFICATION VALUES
7.6
7.61
6.8
Minimal specified limit 2.2 mol
2.15
2.09
2.00
1.98
Propane content (mol)
1.82
1.78
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OPTIMISATION OF LPG EXTRACTION
Design temperature
Reviewed temperature
10.500
10.503
10.467
10.478
10.495
10.451
10.400
HHV (thermies/Nm3)
Improved LNG high heating value
10.300
10.323
10.200
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CONCLUSION
CONCLUSION

• REQUIRED RESULTS ACCOMPLISHED

• DECREASING PRODUCTION LOSSES

• MINIMISING AUTO-CONSUMPTION

• LNG QUALITY IMPROVEMENT

• INCREASING HIGH HEATING VALUE

• MEETING REQUIRED SPECIFICATION

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CONCLUSION
CONCLUSION
LPG HEAT EXCHANGER
PERMIT TO OBTAIN VARIED LNG PRODUCT
COMPOSITIONS
SATISFYING DIFFERENT CLIENTS
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THANK YOU FOR YOUR ATTENTION