VSL releases first results of flow meters calibrated in cryogenic conditions at its LNG test facility

VSL’s LNG Research and Calibration facility has delivered its first SI-traceable LNG flow meter calibration results. A total of six flow meters from five leading flow meter manufacturers were calibrated in the test facility using liquid nitrogen. Apart from the calibrations themselves, effects of upstream flow disturbances and of insulation of the flow meters were investigated. The results are summarized in a publicly available paper which can be downloaded here.

VSL’s LNG Research and Calibration facility in the port of Rotterdam, the Netherlands.

These results mark a big step in the development of the facility towards its ultimate goal of performing midscale (up to 1000 m3/h) LNG flow and composition calibrations. VSL is proud of these achievements and thanks everyone who has contributed to the results.

In the LNG industry it is customary to calibrate custody transfer flow meters at ambient conditions with water as an alternative liquid for LNG. Correction equations derived from literature liquid nitrogen data are applied to compensate for the differences between water and LNG conditions. The reason for calibrating using water at ambient conditions is the lack of facilities that enable research into meter performance and calibrations of meters under cryogenic conditions (at temperatures as low as -190 °C) and at the proper scale. In 2019 VSL completed the construction and commissioning of its LNG Research and Calibration facility. The first set of ‘real’ calibrations consisted of a program of Coriolis and Ultrasonic flow meters using liquid nitrogen. Many partners from industry, academia, and the metrological community contributed to the program. The calibrations were performed as part of the EMPIR project Metrological support for LNG and LBG as transport fuel.

The calibrations showed good repeatability and typical flow meter curves. This demonstrates the facility’s potential of calibrations at sufficiently low SI-traceable measurement uncertainty. These results enable systematic research into LNG metering and open the door to the development and calibration of flow meters suitable for measuring LNG. Meter manufacturers can use the facility to prove flow meter performance and the corresponding measurement uncertainty under cryogenic circumstances.

Menne Schakel, project coordinator of Metrological support for LNG and LBG as transport fuel (16ENG09, LNGIII) is proud: “The successful completion of the first SI-traceable calibration program, using liquid nitrogen in the LNG Research and Calibration facility, marks an important milestone in developing the metrological infrastructure for LNG custody transfer. The results on practical issues, such as flow disturbances and the insulation of the LNG flow meter, provide valuable information for day-to-day application of LNG to trucks and ships. The facility will enables LNG meter manufacturers, LNG end-users, and the metrological and scientific communities to gain confidence in LNG trade, by demonstrating the suitability of LNG meters and complete measuring systems for requirements set by the industry. The facility will play a key role in the large-scale application of LNG in the energy transition, as a clean alternative to fossil fuels.”

Cryogenic testing of upstream flow disturbances now completed for 4 industry-standard LNG flow meters

The effect of upstream flow disturbances was tested on 4 flow meters from 4 different LNG flow meter manufacturers in VSL’s cryogenic research and calibration facility using liquid nitrogen. The upstream flow disturbances investigated comprised a blocking plate and a double bend, and their effects were contrasted against “ideal circumstances” with no upstream flow disturbance and insulated flow meters. In addition, the effect of meter insulation was investigated. The calibration curves of both ultra-sonic and Coriolis meters exhibit good repeatability and typical behavior for the flow meter type. This gives confidence in the facilities master meter calibration method. The results will be published at a later stage. The results will be compared with the water tests which were already successfully completed by NEL, and which were performed in the same metering setups to enable a systematic comparison of flow meter performance under water and cryogenic conditions. Tests on another 2 flow meters are planned, and when these are completed comparison of water and liquid nitrogen data will be started to fully understand the influence of flow disturbances on measurement uncertainty.

The Cryogenic Research and Calibration facility. Components are: 1) Liquid nitrogen storage tank, 2) cryogenic liquid storage tank, 3) primary Standard for mass flow utilizing the gravimetric method, 4) meters-under-test section, 5) working standards, a set of Coriolis mass flow meters, 6) heat exchangers and pumps, 7) Nitrogen warmer and 8) control room.

Milestone ElectroChemical Capacitive gas sensor

In 2018 TNO developed new sensor chips that can be added to the existing multigas sensor array for the measurement of the higher hydrocarbons in LNG. For each of the target gasses in the LNG (i.e. methane, ethane, propane, iso & n-butane, iso & n-pentane and nitrogen) a sensor chip is required. These chips consist of an interdigitated electrode, coated with a responsive coating. This coating absorbs the gas and changes its dielectric constant, which is measured by the electrode. The new butane and pentane responsive coatings are made from mixtures of highly porous ceramic particles embedded in a highly permeable polymer matrix.  Responses of the sensor to butane and pentane concentration variations of 0.1 vol% can be very well distinguished.

The final LNG composition sensor has ten coated electrodes, a temperature and a pressure sensing chip, which enables the calculation of the full LNG composition.

The sensor will be validated in laboratory gas mixtures and will be subsequently inserted in the fuel line of a real test engine.

Testing of new metering skids has been completed by NEL

The excellent collaboration with different flow meter manufacturers in this project resulted in securing six LNG flow meters of different sizes and types, and enabled NEL to design and fabricate suitable metering setups to test these meters in the water test facility under different upstream flow disturbances.

NEL’s UKAS accredited Water Flow Measurement Facility.

A document describing the details of the water test programme including the test parameters and test setups was prepared and approved. Testing at NEL then started in June 18 and successfully completed in July 2018. A total of 28 test cases have been generated covering different upstream disturbances and test temperatures. The metering setups were then shipped to VSL to prepare for the LNG testing.

NEL also completed the analysis of the water test data which have been shared with the project partners. The LNG test programme including test parameters and test setup at the LNG Research and Calibration facility was finalized and approved.  The LNG testing is scheduled to start in May 2019. Once completed, comparison of water and LNG data will be started to fully understand the influence of flow disturbance on measurement uncertainty and provide recommendations to reduce this uncertainty below 0.5%.

Flow disturbances considered in this project.

Metrology for LNG Workshop and Training, 25-26 October 2018, Aberdeen

The LNG 2018 Workshop will take place 25-26 October 2018, Ardoe House Hotel, Aberdeen, Scotland

The workshop for the LNG3 project builds on the success of the previous workshops held during the first and second LNG projects between 2010 and 2017. Each of these workshops attracted over 80 participants from all over the world and presented an excellent platform for networking and sharing information.

More information, and registration here

Upcoming tests

  • Water tests at NEL, scheduled
  • LNG tests at VSL, preliminary schedule

Water tests are scheduled for 15 June – 15 July.
According to the proposed preliminary test program, LNG tests are scheduled for September ~ October -December ~ January 2019 .