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Design and Safety Considerations for
existing LNG Peak Shaving Plants
Hans – Joachim Grossmann
GOC 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 plant
Brief plant
description
Project phases
Pre-Studies
Conformity study
Costing study
The project
Design aspects
Project execution
Project status
Project organization
Summary/conclusions
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The Plant
LNG Peak Shaving Plant
Located at Dormagen
Nievenheim, Germany
Part of ~ 4,000 km HP
Gas Pipeline Grid of
RWE Energy
Mainly cavern storage
Start up in 1976
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Built by CBI Germany
Only two cryogenic LNG
installations in Germany

Brief Plant Description
Gas Treatment and
Liquefaction
Gas treatment with two
adsorber systems
To remove moisture,
aromatics, CO2
Liquefaction with MRL
cycle
MRL Methane/Propane
Liquefaction capacity
2,400 Nm³/h
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Brief Plant Description
LNG Storage
Double wall steel
tank (API 620 Q)
Inner tank 9% nickel
suspended deck
Outer tank CS
Bottom/shell
penetrations
Geo. V. 22,700 m³
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Brief Plant Description
BOG Handling
(exist.)
Partly re-circulated back
to tank
Partly send to pipeline
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Brief Plant Description
NG Send Out System
Two HP Pumps , outside
tanks, 2 x 80m³/h LNG
Two submerged
combustion vaporizers
Send out rate: 2 x 50,000
Nm³/h
Conditioning with LN2
Truck loading system
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Plant Views Submerged C. Vaporizer
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Plant Views Reg. Gas/MRL Compressor
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Pre- Studies
I. First Study to check the
Compliance of the plant with actual rules &
regulations
E.g. EN 1473/NFPA 59A
Safety Study to review actual installed safety features
Active & passive safety equipment
II. Target
Life Extension of the plant
Increased level of automation
Alternative peak shaving concepts
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Plant Views
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Pre- Studies
III. Results
EN 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 study
Costing of various alternatives
Revamping of plant + submerged pumps
Revamping 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 pumps
Install new instrumentation &control system
Revamp 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 composition
Optimization due to input from operators
E.g. gas treatment &liquefaction process
Level of automation
New BOG System
Safety
Hazop Study
SIL Allocation
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Design Aspects LNG Tank
Tank Decommissioning
Data assessment after 30 years operation
Static calculations of existing tank
Install new pumps/pump platform
Recalculated the tank due to change in rules &
regulations
Install additional outer shell stiffeners
Local authorities/ Environmental
Change in Rules & Regulations
Safety Report
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Design Aspects Tank Design
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Design Aspects Tank Design
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Design Aspects FE Calculations
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Project Execution
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 up
Purging with nitrogen
Purging with air
Opening the tank
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Project Execution Temp. Send Out System
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Project Execution Tank Opening – Suspend. Deck
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Project Execution Tank Views
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Project Execution Tank Views
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Project Execution Plant Views
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Project Execution New Pump Platform
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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 studies
basic, detailed engineering
procurement assistance
supervision and start up
Direct procurement of equipment
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Summary /Conclusions
Detailed Pre Studies required
Close cooperation between Client/
Engineering company
Detailed planning of activities
Tailor made solutions required
No critical findings after 30 years of use
Findings/results can be used for other
projects too ( LNG/LEG)
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Summary /Conclusions
We hope that we can report during the next GASTECH
venue the next important step in the project
The restart of the LNG Peak Shaving Plant
Thank you for your attention !
(* Pictures/Diagrams page 3-7 , source: RWE)
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