Precautions for measuring natural gas with a precession vortex flowmeter
The following aspects must be paid attention to when measuring natural gas with the precession vortex flowmeter:
1. Requirements for air flow conditions
a. The measured gas should be a single-phase, continuous round pipe flow through the pipeline.
b. Before the gas flows through the flowmeter, its flow rate must be parallel to the pipe axis, and there must be no vortex flow.
c. The airflow should be subsonic, non-pulsating, and its flow rate changes slowly over time.
2. Installation requirements for flowmeters
This kind of instrument does not have too many special requirements for the process installation and use environment, but any kind of flow measurement instrument has such a common, That is, as far as possible to avoid vibration and high temperature environment with the flow state interference elements (such as compressors, separators, pressure regulator, small head and manifold, elbow, etc.), keep the instrument front and rear straight pipe wall smooth and straight, to ensure that the measured medium is clean single-phase fluid.
3. Flowmeter installation and use should pay attention to matters
Precession vortex flowmeter without mechanical moving parts, small size, corrosion resistance, stable performance; It can directly display the working pressure, temperature, flow rate and gas volume under standard state of the medium; With the advantages of wide measuring range and small measuring error, it has been widely used in production measurement of oil and gas Wells and sales measurement of natural gas. In the field application for many years, we believe that the flow meter is very suitable for relatively clean dry gas measurement, and gradually become a small and medium-sized gas measurement instrument. In order to ensure the accuracy of the precession vortex flowmeter and reduce the measurement error, it is necessary to:
a. Reasonable selection.
Do not make the actual small flow lower than the lower limit of the flow range of the selected runoff meter.
b. The installation is correct
The upstream of the flowmeter should have a metering straight pipe section of at least 10D length. The inner wall of the straight pipe section should be smooth, and there should be no steps, and the weld of the connecting flange should be smoothed, and the flange gasket should not burst into the pipeline. The installation direction of the flowmeter can not be reversed. The test proves that all unreasonable installation will lead to low metering value of the flowmeter.
c. Stay away from the shock source, or install support piers on the flow meter and downstream to avoid the effect of pipeline vibration. Avoid the interference of strong magnetic field on the flowmeter chip.
d. The temperament is relatively clean
In particular, there can be no liquid gas two-phase flow; When the temperament is dirty, the flowmeter should be cleaned immediately.
e. Reduce the impact of air pulsation
The buffer tank can be installed in front of the meter or the length of the metering straight section upstream of the meter can be lengthened.
f. Timely metrological verification of the flowmeter to ensure accurate and reliable value.
