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Measurements in the trade of LNGImproving measurement methods & standards
Oswin Kerkhof, [email protected]
Botlek studiegroep, 7 april 2011
OutlineOutline
LNG custody transfer measurement
LNG quantity measurement – static versus dynamic
LNG quality measurement – sampling versus spectroscopy
R d i t t i ti h i t t?Reducing measurement uncertainties - why important?
Reducing measurement uncertainties – how to?
Metrology for LNG project
LNG Test & Technology Center (LNG TTC)LNG Test & Technology Center (LNG TTC)
LNG transport and custody transferLNG transport and custody transfer
Ocean tankertanker
Receiving Small production sites
Pipeline
terminal
Small Road
(incl. LBG)
gas
Fuel stations Local
ship tanker
(ship and road transport)
regasification point
Ships Trucks Buses
What is the accuracy?What is the accuracy?
Measurement uncertainty total energy LNG
• Between 0.9% (GIIGNL) and 1% or more
Comparison with the case of oil or gas:
• Crude oil custody transfer 0.2 - 0.4% (mass)
• High pressure natural gas 0.6 - 0.7% (on energy)
LNG quantity – static vs dynamicLNG quantity – static vs dynamic
Static
• Ship tank level gauging
• Examples: Radar capacitive float laser
State-of-the-art technology
• Examples: Radar, capacitive, float, laser
Dynamic
• Flow meteringChallenging
• Flow metering
• Examples: ultrasonic, coriolistechnology
LNG quantity – static measurements
Tank based measurement : state‐of‐the‐art in LNG custody transfer
LNG quantity – static measurements
• Expanded uncertainty (k=2) 0.42% (GIIGNL custody transfer handbook 3rd edition)• Ship based measurements• Tank strapping => tank deformation => errors in tank tables• Tank strapping => tank deformation => errors in tank tables• Tank level gauging: Floating, microwave radar, electrical capacitance, laser
Uncertainty sources consideredUncertainty sources considered
1. Gauge table2. Correction tables for list and trim3 Oth l ti ( i d h i d ift)3. Other volume corrections (e.g. sagging and hogging, drift)4. Volumetric temperature expansion coefficient of the tank and reference
temperature of the tank5. Expansion coefficient of the level gauge6 G t t di t ib ti ( l d d t f l l6. Gauge temperature distribution (relevance depends on type of level
gauge)7. Mean temperature of the dimensional structure of the tank8. Intrinsic uncertainty level gauge9 D ift i l l9. Drift in level gauge10. Procedure to measure trim and list (location, stability, traceability)
Uncertainty budget: volume unloadedvolume unloaded
See next slide
Examples from aExamples from a study by DNV (Det Norske Veritas)
Ambient/seawater temperature within ± 20 °C f f± 20 °C of reference temperature of gauge table (20 °C)
Uncertainty calculation shows the importance of correcting for ambient/seawater temperature for a Membrane tank
Uncertainty budget: level gaugelevel gauge
HorizontalHorizontal displacement of level gauge:Trim: d = 2 mList: d =1 mList: d 1 m
According to a study bystudy by Metropartner
Uncertainty calculation shows the importance of correcting for calibration and location-effect on trim and list
LNG quantity – dynamic measurements
Flow metering: state‐of‐the‐art in other hydrocarbon custody transfer
LNG quantity – dynamic measurements
• LNG flowmeters available and used in special projects, proces monitoring and custody transfer (unofficial) verification at LNG terminals
• Potential calibration uncertainty (k=2) with real LNG reference system ~0 2%Potential calibration uncertainty (k 2) with real LNG reference system 0,2%• Flowmeters as alternative for or verification of off‐shore tank measurements• For off shore LNG applications (FPSO – Floating Production Storage Offloading)• For small and mid‐scale LNG applications
Gas metering station in Jordania LNG allocation metering skid in Qatar LNG Floating Production Storage Offloading
LNG quality measurementsLNG quality measurements
Sampling
• Liquid line samplingE i ti
State-of-the-art technology• Evaporization
• Gas chromatography analysistechnology
Non-sampling
• Liquid line Raman spectrometryChallenging
• Liquid line Raman spectrometry• In-line measurement technology
LNG quality measurementsLNG quality measurements
Sampling systems
Raman spectroscopyRaman spectroscopy system
Reducing measurement uncertaintiesReducing measurement uncertaintiesHow important is that?
• 1% uncertainty on total value of global trade of LNG (200 mtpa in 2010)
= 440 M€/year (2010) 900 M€/year (2015)
• Mass balance considerations
Reducing measurement uncertaintiesReducing measurement uncertaintiesHow to do it?
• Volume - flow metering – potential for roughly factor two
D it i i f d t t ti l f hl f t t• Density - improving reference data – potential for roughly factor two
• Mass – flow metering – potential for roughly more than factor two
• Gross calorific value - improved samping techniques or Raman spectroscopy – improvement factor ???
Metrology for LNG project
• Developing traceability for LNG
Metrology for LNG project
Volumep g y
flow meters (WP1)• Testing and evaluating LNG
quantity metering systems (WP2)
WP5
Measurement GuidelinesMass
Density• Improving LNG composition
measurement systems (WP3)• Reducing uncertainties in LNG
density calculations (WP4)
WrittenStandards
Mass
density calculations (WP4)
• Improving LNG composition measurement systems (WP3)
Gross Calorific
Legal Metrology
y ( )• Reducing uncertainties in calorific
value calculations (WP4)Calorific
Value
Overall objectiveReduction of the measurement uncertainty by a factor twoEnergy
Metrology for LNG
W W W. L N G M E T R O L O G Y. I N F O
• Detailed project information• Objectives tasks activities• Objectives, tasks, activities• Progress reports, project results
• Project news• Photo gallery• Discussion forum• Publications and articles
• Project presentations and articles• Other LNG measurement articles• Other LNG measurement articles• Relevant standards and guidelines
Metrology for LNG projectMetrology for LNG project
WP1 Developing traceability for LNGDeveloping traceability for LNG
flowmeters
Traceability for LNG FlowmetersTraceability for LNG Flowmeters
A three step approach:
1. Primary standard2 S t f t di th f2. System for extending the range of
flowrates3 Full scale facilities3. Full scale facilities
2nd step:2 step: 1st stage upscaling standard
RM RM
2nd stage information
RM
RM
RM
RM
RM
RM RM
RM
1st stage information
RM= Reference Meter
3rd step: Full scale facilities
Ultrasonic master meters
Primary mass flow
TNO testing area
LNG Piston prover
Primary mass flowstandard (EMRP WP1)
1st stage upscalingstandard (EMRP WP1)
LNG compositiontesting area
standard (EMRP WP1)
Installation areaflowmeters under test
2nd and 3rd stage upscaling
Conclusies
Di LNG t d t f t l i b hikbDiverse LNG custody transfer systeem oplossingen beschikbaar maar …Veel ruimte voor verbetering
Nieuwe en verbeterde meetsystemen en methodenyVerbeterde metrologische infrastructuur
Nederland heeft grote ambities om LNG distributieland te wordenInvesteren in kennis op gebied van LNGInvesteren in kennis op gebied van LNGOntwikkelen van excellente kennis op gebied van LNG metingenBetrouwbaar meten staat aan de basis van handelsverkeer