Why does the flow meter in our unit show such a large error when compared with the actual liquid level – there’s an error of around 8 tons? Please advise.
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Accuracy issues with Coriolis mass flowmeters
8 tons is a unit of mass; you need to convert it to a unit of volume. Moreover, this error is relative to the total amount; it depends on the size of the total!
It’s called a mass flow meter after all! Sometimes the error isn’t technical, you know. The best approach is to calibrate each other and verify the other party’s flow meters.
Factors such as whether the level gauge’s output is stable, whether it is installed properly, whether the ranges of the DCS and the central control system match, whether the calculation methods and results for the cumulative volume on-site are consistent with those at the central control station, whether the level gauge is accurate, whether the inflow and outflow amounts are balanced or not, and the shape of the tank, can all have an impact
There are several aspects to check: 1. For mass flow meters used for measurement, it is preferable that the flow rate remain stable and not change rapidly. For the 2PCS unit, it should be determined whether accumulation is done using analog signals or pulses; if analog signals are used, it’s advisable to switch to pulse-based accumulation as analog methods are generally inaccurate. 3. Is the liquid level measurement accurate? Measure the actual size of the orifice at the top of the tank before making further calculations. 4. Check whether the flow meter is installed properly; there should be no stress on the flanges. 4. The pipeline connected to the flow meter should not vibrate. 5. The flow meter should not be used to measure two-phase flow
I calculate the production amount every day based on the liquid level data, in order to compare it with the flow meter readings; the error is generally not significant. What’s important is to determine the liquid level coefficient of the storage tank accurately – one cannot rely on theoretical calculations. A circle has the largest area, but in reality, no storage tank is perfectly circular
Are you sure the flow meter is in a full-bore condition?
The accuracy of Coriolis mass flowmeters is generally not an issue; most problems arise from installation or usage