Metrological support for LNG custody transfer and transport fuel applications. Jianrong Li. Chemie themadag, VSL 17 September 2015

Transcription

1 Metrological support for LNG custody transfer and transport fuel applications Jianrong Li Chemie themadag, VSL 17 September 2015

2 LNG transport and custody transfer Ocean tanker Receiving terminal Pipeline gas Road tanker Small ship Bunkering/Fuelling stations Trucks Ships Buses 2/ 18

3 Measurements involved in LNG custody transfer Energy metering setup (simplified) Quantity (v, m) Pressure Temperature T p GC Flow computer Composition Density Calorific value Speed of sound LNG LNG 3/ 18

4 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 Harmonized Methane Number Primary Density standard Improved Density correlations / Improved Equation of State 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 / 18

5 Project objectives Reducing the uncertainty of LNG custody transfer measurements by a factor two (reducing the exposure on the value of one ship filled with LNG ~ ) Enabling the development of LNG as transport fuel Development and validation of calibration standards for LNG mass and volume flow (mid-scale) Development and validation of LNG composition standards Development and validation of a method for determining the methane number Validated and improved model for LNG density prediction; examination of uncertainties and traceability of enthalpy and calorific value calculations Partners: And with many Industry supports 5/ 18

6 LNG composition measurement Aims: Produce an accurate, lab-based sampling and analysis reference method to test and calibrate commercially available sampling/ composition measurement systems Develop methods to sample and vaporize LNG in a representative and homogeneous fashion Validate Raman spectroscopy methods for composition analysis and compare the results obtained to those from GC methods Study the effects of long-term storage on LNG composition Sampling point New sampler 6/ 18

7 Reference gas composition Reference gases: Components Mol fractions (% mol/mol) Nitrogen Methane Ethane Propane iso-butane n-butane iso-pentane n-pentane Many LNG origin sources 7/ 18

8 Quantity (unit) LNG Composition reference standard Raman Probe Laboratory tests: LNG reference gas in Liquefier/ measurement cell Liquefier and Raman measurement cell Insulation shield LNG reference gas (known composition) Measurement 1 (Reference) Reference Liquefier Developed within the project Measurement 2 (Result) Sampler & Vaporizer Supercritical vaporizing LNG calibration gas Reference Result 8/ 18

9 Quantity (unit) LNG Composition reference standard Field tests: Supercritical vaporizing Liquid Sampler P > P c T > T c Release P Reference Vaporizer LNG calibration gas LNG loop Measurement 1 (Reference) Measurement 2 (Result) Commercial Sampler Vaporizer Reference Result 9/ 18

10 Methane Number MN (NPL) Methane Number (MN) Algorithm Ranking of knocking resistance of gases (expressed in MN/ like octane number for petrol) Developed MN algorithm based on experimental data from detailed study by AVL Includes correction for nitrogen and higher hydrocarbons Algorithm shows good agreement with other popular methods (e.g. DGC, MWM) MN-algorithm DGC MWM Emirates Norway Libya Oman Alaska LNG origin sources DGC - Danish Gas Company MWM - Motorenwerke Mannheim MN (MWM) 10/ 18

11 Methane Number Selected mixtures for MN study Selected mixtures represent commercially available mixtures and their variations in composition well Resulting MNs cover a very broad range allowing for sufficient feedback for the algorithm Selected mixtures Components Mol fractions (% mol/mol) Nitrogen Methane Ethane Propane iso-butane n-butane iso-pentane n-pentane / 18

12 RCM and SI engine tests Determination of knocking resistance: Ignition delay time measurements Using Rapid Compression Machine (RCM) 3 stoichiometries 5 temperatures between 500K and 900K Pressures bar Spark-Ignition (SI) engine measurements Test with 2 types of engines Test with reference gas (CH 4 + H 2 ) Test with all selected mixtures Test with different engine speeds, intake cam position, and center of combustion 12/ 18

13 Density, Enthalpy and Calorific Value Physical properties and quantities play important roles in LNG custody transfer. Aims: Innovatively measuring LNG density Improved model for LNG density prediction (equation-ofstate & uncertainty) Produce a sensor for simultaneously determining the density and speed-of-sound of LNG samples in liquid phase at different cryogenic temperatures (91 < (T/K) < 110) Uncertainty and traceability analysis of enthalpy and calorific value calculations 13/ 18

14 LNG densimeter Specifications T-range: 90 K to 300 K p-range: 0.05 MPa to 12 MPa Homogeneous + saturated liquid (incl. vapor pressure), hom. gas Δρ/ρ < 0.05 % (incl. mix. unc.) Single-Sinker Densimeter for cryogenic liquid mixtures at Ruhr-University Bochum 14/ 18

15 Single-Sinker Densimeter for Cryogenic Liquid Mixtures of Richter, Kleinrahm, Lentner and Span (2015) Novelty! MSC: first time operated at cryogenic temperatures 15/ 18

16 Sensor for simultaneously measuring Cryogenic temperatures (91 < (T/K) < 110) Cell is immersed into the LNG (differs from commercial ultrasonic flow meters) Principle: Measurement of acoustic impedance Z and the sound velocity w (double pulse-echo technique): ρ = Z / w Validation: non-cryogenic temperatures and then at cryogenic temperatures (pure liquids) Measurements of at least four LNG like mixtures at cryogenic temperatures Uncertainty analysis: speed-of-sound and density Density: in the order of 0.2 % Speed-of-sound: in the order of 0.5 % 16/ 18

17 Concluding remarks Designing and manufacturing of LNG composition measurement facilities are underway An algorithm for calculating the methane number from the composition of a LNG mixture has been developed Improvement of tools and methods for measuring and calculating LNG physical properties and their uncertainty and traceability analysis are in progress 17/ 18

18 Thank you! Questions? Contact details: VSL Thijsseweg JA Delft The Netherlands Mrs. Dr. Jianrong Li Tel Acknowledgement: Markus Richter (RUB) Bjoern Gieseking (NPL) Jürgen Rauch (PTB) Peter Eilts (TUBS)