Fluctuations in Emerson Coriolis mass flow meters
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The process workshop is equipped with an Emerson Coriolis mass flow meter with a measurement range of 90–3000 standard cubic meters. The fluid in question is hydrogen, at a pressure of around 8.5 kilograms and a temperature of about 30 degrees. Initially, the performance was quite stable; fluctuations occurred only when the flow rate was between 2000 and 2100 cubic meters. Yet, there were no significant changes in the process conditions at that time. I hope everyone can help me analyze the reason for this. We changed the damping coefficient from 2.8 to 5.6, but the problem persisted. Is resonance the cause?
The process pipeline is DN100, but the instrument has been reduced in diameter to DN25
We have calculated that the flow velocity can reach 100 meters per second at its maximum
Rosemount mass transmitters can operate with full pipe diameters; therefore, to consider economic aspects, the pipe diameter is usually reduced. However, reducing the diameter requires a certain length of straight pipe section
Do you think there is any issue with the gas pipeline? What are the requirements for straight pipe sections in mass flow meters?
The problem is likely that the flow meter has an excessively small diameter, resulting in high flow rates and pressure losses, which in turn cause the flow meter to vibrate. Based on the parameters provided by the poster, a 3\" flow meter is estimated to be required. Mass flow meters are used to measure gases, especially hydrogen; the diameter cannot be too large, nor can the flow rate be too low. It is not recommended to use mass flow meters to measure gases, especially those with a low molecular weight.
Changing the damping coefficient cannot resolve the problem fundamentally; this situation is likely due to resonance occurring at this flow rate； Based on the data you provided, at 2000 cubic meters per hour, the flow velocity exceeds 150 m/s ； What is the actual flow rate range at the site? It is recommended to select a flow meter with an appropriate caliber based on the actual conditions.