Development of an LNG sampling and composition measurement reference standard. Jianrong Li LNG II Workshop 22 August 2017, VSL, Delft, NL

Transcription

1 Development of an LNG sampling and composition measurement reference standard Jianrong Li LNG II Workshop 22 August 2017, VSL, Delft, NL

2 Contents Introduction Basic principles behind the design Design and validation approaches Concluding remarks and future work

3 Energy supply Cleaner fuel Metrological support: Metrology for LNG Roadmap TRIGGERS Small scale LNG - LNG as transport fuel New LNG applications with New Business Models Large scale LNG - Production and regasification plants TARGETS Traceable LNG custody transfer measurements Clear uncertainty budgets Uncertainty reduction by factor two Primary Density standard Harmonized Methane Number Improved Density correlations / Improved Equation of State EU / NL Project EU / NL Project LNG Composition evaluation state-ofthe-art Ship tank volume measurements uncertainty evaluation Primary mass flow standard EU / NL Project LNG Composition calibration systems Mid-scale volume flow standard Mid-scale mass flow standard Large scale flow standards Reduced uncertainty Liquefier & Density Smart sensors

4 Measurements involved in LNG custody transfer Energy metering setup (simplified) Quantity (v, m) Pressure Temperature T p GC Flow computer Composition Density Calorific value Wobbe number Methane number Speed of sound LNG LNG

5 LNG composition measurement What is important? Accurate sampling Representative & Homogeneous Accurate vaporizing (for GC method) Complete and Instant Conditioning of the gaseous sample Constant Pressure & Temperature Accurate measurements Accurate method with lower uncertainty

6 LNG sampling precautions Sampling is the most critical part of the LNG measurement chain Avoid changing composition in every step Control P, T to get representative sample Locate sample probe at points where LNG is in a sub-cooled condition Ensure LNG remains sub-cooled in sampling pipe during sampling (pipe with good insulation, as short as possible, diameter as small as possible) Guarantee complete and instant vaporizing (sufficient heat supply)

7 LNG flow rate LNG sampling period Sampling period Time Sampling during constant flow rate

8 LNG phase diagram Reference: Angel Benito and Enagás, S.A., Accurate determination of LNG quality unloaded in Receiving Terminals: An Innovative Approach

9 LNG composition Methane Ethane Propane C 4 + Nitrogen Water, Oxygen, Carbon dioxide Other impurities (sulfur components, aromatics, particulates )

10 LNG composition measurement techniques Gas chromatography Raman spectroscopy

11 Gas Chromatography vs. Raman Spectroscopy Gas Chromatography Raman Spectroscopy Currently used in ISO standard Measure gas phase Higher cost Picture source: Shell Global Solutions Under developement Measure liquid & gas phase Lower cost

12 Quantity (unit) LNG sampling and composition measurement reference standard Design and validation of the reference standard: LNG based reference gases (known composition) Measurement 1 (Reference) Reference Liquefier Measurement 2 (Result) Sampler & Vaporizer Supercritical vaporizing P > P c T > T c Release P LNG based calibration gases Reference Result

13 Reference gas composition Reference gases: Components Mol fractions (% mol/mol) Nitrogen Methane Ethane Propane iso-butane n-butane iso-pentane n-pentane There are many LNG origin sources giving different LNG compositions

14 Selected LNG based reference gas mixtures A set of 8 LNG like gas mixtures compositions have been defined (see Table 1) Table 1. Definition of a set of 8 LNG mixtures for validating the reference standard for validating/qualifying LNG sampling and composition measurement systems. Components Mix #1 Mix #2 Mix #3 Mix #4 Mix #5 Mix #6 Mix #7 Mix #8 Nitrogen Methane Ethane Propane iso-butane n-butane iso-pentane n-pentane Note: The values in this table are in [% mol/mol] to cover low medium high Calorific Values

15 Sampling and vaporizing approach followed here Supercritical vaporizing P > P c, T > T c Reference: Installations and equipment for liquefied natural gas - Suitability testing of LNG sampling systems, NEN-EN (en),

16 Requirements for LNG sampling system (EN12838) Reference: Installations and equipment for liquefied natural gas - Suitability testing of LNG sampling systems, NEN-EN (en),

17 Quantity (unit) Application of the LNG sampling and composition measurement reference standard After the reference standard has been validated Reference Sampler &Vaporizer LNG based calibration gases LNG loop Measurement 1 (Reference) Measurement 2 (Result) Service Commercial Sampler &Vaporizer Reference Result

18 LNG reference sampler and vaporizer

19 Concluding remarks and future work An LNG sampling and composition measurement reference standard has been built Commissioning test with liquid nitrogen has been successfully carried out Test with real LNG is on-going Testing, calibration and certification services will be provided for commercial systems

20 Contact details: VSL Thijsseweg JA Delft The Netherlands T F E info@vsl.nl I Thank you for your attention! Questions?? Acknowledgement: Dr. Hugo Ent Dr. Adriaan van der Veen Gerard Nieuwenkamp Oswin Kerkhof ASaP B.V. Dr. Jianrong Li Tel jli@vsl.nl