design and safety considerations for existing lng peak
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Grossmann/Gastech2005 Revamping LNG Peak Shaving Plant 1
Design and Safety Considerations for existing LNG Peak Shaving Plants
Hans – Joachim GrossmannGOC Engineering GmbH
Gastech 2005 March 13-17, Bilbao Spain
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Design and Safety Considerations for existing LNG Peak Shaving Plants
-A Project Example-
The plantBrief plant descriptionProject phasesPre-StudiesConformity studyCosting study
The projectDesign aspectsProject executionProject statusProject organizationSummary/conclusions
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The Plant
LNG Peak Shaving PlantLocated at DormagenNievenheim, GermanyPart of ~ 4,000 km HP Gas Pipeline Grid of RWE EnergyMainly cavern storage
Start up in 1976Built by CBI GermanyOnly two cryogenic LNG installations in Germany
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Brief Plant Description
Gas Treatment and Liquefaction
Gas treatment with two adsorber systemsTo remove moisture, aromatics, CO2Liquefaction with MRL cycleMRL Methane/PropaneLiquefaction capacity2,400 Nm³/h
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Brief Plant Description
LNG Storage
Double wall steel tank (API 620 Q)Inner tank 9% nickel suspended deckOuter tank CSBottom/shell penetrationsGeo. V. 22,700 m³
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Brief Plant Description
BOG Handling (exist.)Partly re-circulated back to tankPartly send to pipeline
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Brief Plant Description
NG Send Out SystemTwo HP Pumps , outside tanks, 2 x 80m³/h LNGTwo submerged combustion vaporizersSend out rate: 2 x 50,000 Nm³/hConditioning with LN2Truck loading system
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Pre- Studies
I. First Study to check the Compliance of the plant with actual rules & regulationsE.g. EN 1473/NFPA 59ASafety Study to review actual installed safety featuresActive & passive safety equipment
II. TargetLife Extension of the plantIncreased level of automation Alternative peak shaving concepts
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Pre- Studies
III. ResultsEN 1473 allows no penetrations of the primary and secondary container walls ( >> submerged tank pumps)NFPA 59A allows penetrations, however the design spill shall be defined as the full liquids content of the tank ( >> with submerged pumps the design spill reduced to 10min. Nom. Pump capacity)Entire revamping needed instrumentation & control system Partly revamping needed for mechanical equipment
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Pre- Studies
IV. Costing studyCosting of various alternatives
Revamping of plant + submerged pumpsRevamping of plant with additional safety features ( water curtains, foam systems, thermal insulation of impoundment area )
Other alternatives such as close down of plant
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The Project Overview
Client decided to take out the plant for one winter season to: Empty and warm up the LNG tank
Install submerged pumpsInstall new instrumentation &control systemRevamp partly mechanical equipment/ piping, control building etc. Install new BOG handling system ( was added to the project 2Q/2004)
Project duration 1Q/04 – 4Q/05
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Design Aspects Process
Process simulation Change in gas compositionOptimization due to input from operatorsE.g. gas treatment &liquefaction process Level of automation New BOG System
SafetyHazop StudySIL Allocation
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Design Aspects LNG Tank
Tank Decommissioning Data assessment after 30 years operation
Static calculations of existing tankInstall new pumps/pump platformRecalculated the tank due to change in rules & regulationsInstall additional outer shell stiffeners
Local authorities/ Environmental Change in Rules & RegulationsSafety Report
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Project Execution Emptying Tank
Decommissioning of tank starts at approx. 2,5 m liquid level ( April 2004)Temporary connection between RT Loading pumps and HP send out pumps Result : Tank more or less 100 % liquid emptied Warming upPurging with nitrogenPurging with air Opening the tank
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Project Execution Tank Opening – Suspend. Deck
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Project Execution -Laser Scanning (Test Project)
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Project Execution -Laser Scanning (Test Project)
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Project Execution -Laser Scanning (Test Project)
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Project Execution -Laser Scanning (Test Project)
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Project Execution -Laser Scanning (Test Project)
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Project Organisation
Entire project execution with one Engineering company including:
pre studiesbasic, detailed engineeringprocurement assistancesupervision and start up
Direct procurement of equipment
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Summary /Conclusions
Detailed Pre Studies requiredClose cooperation between Client/ Engineering companyDetailed planning of activities Tailor made solutions requiredNo critical findings after 30 years of useFindings/results can be used for other projects too ( LNG/LEG)