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1
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MJCronin
Mechanical
- Apr 9, 2001
- 5,087
An oldie, but a goodie .....
SKIKDA, ALGERIA -- LNG PLANT BOILER EXPLOSION - JANUARY 19, 2004
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What Went Wrong In Skikda LNG Explosion (27 employees died, 56 injured and cost nearly $1Bilion
The Skikda LNG complex comprises 6 LNG liquefaction trains. Units 10, 20, 30 and 40 are located parallel to each other on the west side of the LNG storage tank area. Units 5 and 6 are located remotely on the east side of the LNG storage tanks. The administration, maintenance and security buildings are located adjacent to the most westerly unit ( Unit 40 ). Units 10, 20 and 30 ( utilising mixed refrigerant technology ) were brought online in 1971/1973. Units 40, 5 and 6 ( utilising single mixed refrigerant technology ) were brought online in 1981.
On 19th Jan 2004 with Unit 40 operating normally, a steam boiler providing high-pressure steam for the Unit 40 refrigeration compressor turbine driver exploded. The boiler firebox casing was breached, triggering a fireball and a second, much larger, vapour cloud explosion (VCE ) which spread outward, completely destroying Units 40, 30 and 20 ( 43 % of the site's production capacity ). It also destroyed the administration, maintenance and security buildings, trapping workers under the debris. Damage to Units 10, 5 and 6 and the LNG storage tanks was minimal. However, surrounding facilities including a nearby power plant, an LNG loading berth at Skikda harbour and numerous homes and other buildings in the community were also damaged. The neighbouring refinery was shut down as a precaution. Unit 6 of the LNG Complex was restarted in May 2004. Units 5 and 10 were restarted in September 2004. Units 20, 30 and 40 were eventually rebuilt.
The possible cause is the release of mixed refrigerant vapours and LNG (from a cold box heat exchanger leak ingested by the air intake of the forced draft combustion air fan at Unit 40 ) which were steam boilers, creating an explosive mixture in the boiler firebox.
Accident Analysis:
1 ) The Unit 40 steam boiler was located very close to the LNG liquefaction and separation sections of the Unit 40 process plant ( newer LNG plant designs use gas turbines to drive the refrigerant compressor these are more efficient, more robust and eliminate the need for a steam boiler ).
2 ) The loss of primary containment at the cold box released hydrocarbon vapour into a congested space between Unit 40, the control room and the boiler ( exacerbating the impact of the VCE ).
3 ) Still ambient conditions ( no wind to disperse leaking vapours ).
Root causes are:
1 ) Poor plant layout ( proximity of neighbouring LNG liquefaction trains and occupied buildings )
2 ) Inadequate inspection and maintenance (cold box heat exchanger ).
Lesson Learned :
1 ) Escalation impact studies should be carried out to determine the best plant layout and equipment spacing to minimise the risk of a major accident.
2 ) Land use planning regulations specifying minimum separation distances between high hazard facilities and residential buildings should be enforced.
Ref. Ichem free LL library.
#SkikdaLNG #lessonslearned
No alternative text description for this image
MJCronin
Sr. Process Engineer
SKIKDA, ALGERIA -- LNG PLANT BOILER EXPLOSION - JANUARY 19, 2004
___________________________________________________________________________________________________________
What Went Wrong In Skikda LNG Explosion (27 employees died, 56 injured and cost nearly $1Bilion
The Skikda LNG complex comprises 6 LNG liquefaction trains. Units 10, 20, 30 and 40 are located parallel to each other on the west side of the LNG storage tank area. Units 5 and 6 are located remotely on the east side of the LNG storage tanks. The administration, maintenance and security buildings are located adjacent to the most westerly unit ( Unit 40 ). Units 10, 20 and 30 ( utilising mixed refrigerant technology ) were brought online in 1971/1973. Units 40, 5 and 6 ( utilising single mixed refrigerant technology ) were brought online in 1981.
On 19th Jan 2004 with Unit 40 operating normally, a steam boiler providing high-pressure steam for the Unit 40 refrigeration compressor turbine driver exploded. The boiler firebox casing was breached, triggering a fireball and a second, much larger, vapour cloud explosion (VCE ) which spread outward, completely destroying Units 40, 30 and 20 ( 43 % of the site's production capacity ). It also destroyed the administration, maintenance and security buildings, trapping workers under the debris. Damage to Units 10, 5 and 6 and the LNG storage tanks was minimal. However, surrounding facilities including a nearby power plant, an LNG loading berth at Skikda harbour and numerous homes and other buildings in the community were also damaged. The neighbouring refinery was shut down as a precaution. Unit 6 of the LNG Complex was restarted in May 2004. Units 5 and 10 were restarted in September 2004. Units 20, 30 and 40 were eventually rebuilt.
The possible cause is the release of mixed refrigerant vapours and LNG (from a cold box heat exchanger leak ingested by the air intake of the forced draft combustion air fan at Unit 40 ) which were steam boilers, creating an explosive mixture in the boiler firebox.
Accident Analysis:
1 ) The Unit 40 steam boiler was located very close to the LNG liquefaction and separation sections of the Unit 40 process plant ( newer LNG plant designs use gas turbines to drive the refrigerant compressor these are more efficient, more robust and eliminate the need for a steam boiler ).
2 ) The loss of primary containment at the cold box released hydrocarbon vapour into a congested space between Unit 40, the control room and the boiler ( exacerbating the impact of the VCE ).
3 ) Still ambient conditions ( no wind to disperse leaking vapours ).
Root causes are:
1 ) Poor plant layout ( proximity of neighbouring LNG liquefaction trains and occupied buildings )
2 ) Inadequate inspection and maintenance (cold box heat exchanger ).
Lesson Learned :
1 ) Escalation impact studies should be carried out to determine the best plant layout and equipment spacing to minimise the risk of a major accident.
2 ) Land use planning regulations specifying minimum separation distances between high hazard facilities and residential buildings should be enforced.
Ref. Ichem free LL library.
#SkikdaLNG #lessonslearned
No alternative text description for this image
MJCronin
Sr. Process Engineer
