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Gas meter calibrated for Baltic Sea pipeline


The Baltic Sea pipeline (Nord Stream) will annually transport about 55 billion cubic meters of gas when it has been completed. It is about 1220 km long, has two parallel pipes, starts in the Russian city of Vyborg and reaches Germany in Lubmin near Greifswald. Germany and the whole of the European Union hope for a more stable gas supply in future and therefore also more energy security through the omission of transit countries.

For the metrological detection of the transported gas volumes, there are several parallel test sections located at Vyborg and Lubmin each with 2 ultrasonic gas meters in series. Eight test sections are planned for the Vyborg station.
The 1.9 t heavy meters employed there with a nominal width of 400 were constructed for a maximum pressure of 250 bar and a maximum flowrate of 9000 m³/h.
Because calibrating the gas meters is not possible under working conditions, the Reynolds number-dependent behaviour was scientifically examined.
To do this, the gas meters were calibrated with air at 1 bar and with natural gas at 16 bar and 50 bar, in addition to zero-flow checks carried out at 50 bar and 250 bar.
As a result, a metrologically secured extrapolation was accomplished, which allows a calibration of the gas meters with an uncertainty of 0.3%. A total of 16 meters were calibrated according to this procedure.

Contact person:

Bodo Mickan, Dept. 1.4, WG 1.42, E-Mail: bodo.mickan@ptb.de