Modeling of the flow comparator as calibration device for high pressure natural gas flow metering in Modelica

Sukhwinder Singh,Gerhard Schmitz,Bodo Mickan

doi:10.1016/j.flowmeasinst.2020.101808

Sukhwinder Singh, Gerhard Schmitz + Show 1 more

Open Access

https://doi.org/10.1016/j.flowmeasinst.2020.101808

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Abstract

The German national metrological institute, Physikalisch-Technische Bundesanstalt, is developing a new concept a for a volumetric primary standard to calibrate high pressure gas flow meters. The TUHH is supporting these Research & Development activities with its competence to elaborate computational models for detailed analysis of complex electromechanical systems including fluid flow aspects. The new primary standard is called Flow Comparator and uses an actively driven piston prover to measure the gas flow rate using the time the piston needs to displace a defined enclosed volume of gas in a cylinder. A computational model is developed in Modelica® to investigate the Flow Comparator’s dynamic behavior and interaction with other components in the loop. The validation of the developed model shows good compliance with measured piston velocity and differential pressure at the piston. The model is used to optimize the frequency inverter’s control voltage trajectory to increase the available calibration time.

Highlights

Natural gas is one of the most frequently used energy carriers worldwide and is usually transported in high pressure pipelines or as liquefied natural gas in tank vessels
At the top of the calibration chain in Germany is the primary standard for high pressure natural gas flow metering
The High-Pressure Piston Prover (HPPP) can be operated with an inlet pressure up to 90 bar and flow rates up to 480 m3/h [3]

Summary

Introduction

Natural gas is one of the most frequently used energy carriers worldwide and is usually transported in high pressure pipelines or as liquefied natural gas in tank vessels. In regards to the trade with natural gas, the uncertainty of high-pressure natural gas flow meters is of major importance. At the top of the calibration chain in Germany is the primary standard for high pressure natural gas flow metering. It is a High-Pressure Piston Prover (HPPP), which is installed and operated at the calibration facility for gas meters pigsarTM in Dorsten, Germany [1–3]. Due to the increasing size and flow rates of the gas flow meters and the limited operation range of the current national standard, a new concept for calibrating gas flow meters is being developed, the so-called Flow Comparator (FC).

Experimental setup

Modelica

Model description

Validation

Optimization

Conclusion