LNG Mass Flow Standard Improving the kilogram for LNG Dushyant Parkhi Flow Engineer VSL
Outline - Why do we need mass flow calibration standards for LNG? - What is the role of VSL in LNG Goal Road Map - How will the goal be reached? LNG-Primary Scale Loop (PSL) LNG-Mid Scale Loop (MSL)
Why calibration standards? Trust in Trade LNG Custody Transfer : Contractual Requirements Legal Requirements Reliable measurements production, storage and offloading (FPSO) vessels LNG Tank gauging system Based on guidelines : GIIGNL Best Uncertainties ±0.5% Commodity Market LNG as transport fuel volume flow meter mass flow meter Expected Uncertainties ~ 0.15% used for allocation and control but not for custody-transfer measurement.
Role of VSL in LNG Metrological traceability requires an established calibration hierarchy. BIPM VSL VSL and/or calibration laboratories Manufacturers End users SI National/ Primary Standards Secondary / Working Standards SI Instruments in the field Calibration hierarchy From small to higher uncertainty calibration hierarchy
Goal of VSL: Realization of an gravimetric LNG mass flow standard and calibration facility Requirements: Get measurement uncertainty for the LNG kilogram below 0.1% SI National/ Primary Standards Secondary / Working Standards SI Instruments in the field
Road Map: 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 Methane Number harmonization / ISO Primary Density standard Improved density correlations / Improved Equations of State LNG Composition evaluation state-ofthe-art LNG Composition calibration systems Ship tank volume measurements uncertainty evaluation Primary mass flow standard Mid-scale volume flow standard Mid-scale mass flow standard Large scale flow standards 2009 2013 2014 2015 2018
Execution: Three Step Approach Primary flow Standard 10-25 m 3 /hr 4-12 ton/hr Mid-scale flow standard 5 200/400 m 3 /hr 2 100/200 ton/hr Full scale facilities 200-4000 m 3 /hr 100 2,000 ton/hr
Step1: Primary Flow Standard (PSL) Calibration and Measurement Capability: Q ~ 10-25 m 3 /hr CMC ~ 0.15% Supplying tank Pump MUT MUT Weighing tank Scale
LNG-PSL Description Description: Parts Description: Process Description: Sources of uncertainties Supplying tank Weighing tank Uncertainty Sources Partly undefined direction of flow during switch over Pump Flow meter to be calibrated Reference for calibrations Fixed connection causing nonconstant forces on scale Uncertainty in mass collected between MUT and Reference
Step1a: PSL-Improvement Reduce uncertainties in flow measurements (<1%) Provide traceability to Mid Scale Loop (200 m 3 /h) Supplying tank Pump MUT MUT Weighing tank Scale
Reduction uncertainty related to non-constant & parasitic forces WP1 Characterization mechanical hysteresis and stiffness matrix WP2-4 Parasitic Force Reduction System 1. Reduction tank movement 2. Parasitic force compensation Flex loop Weighing tank 1 flange 2 x,y,z motion stage 3 LNG tank 4 position measurement 5 flexible piping 6 load cell 7 foundation Example1 : Parasitic force reduction based on position measurement
Reduction uncertainty related to non-constant & parasitic forces WP1 WP2-4 Decoupling the pipe to eliminate the parasitic forces Retraction system Weighing tank Retraction due to Force of decoupling smooth bending of swivel Dry break coupling Example 2: Parasitic force elimination
Reduction uncertainty related to switching and temperature reading WP5 Reducing timing uncertainty Improve temperature reading and reduce dead volume uncertainty Pre run mode Run mode to get stable (= calibration) flow
Step-2 : Mid Scale Loop