Solve the problem of flow rate detection for concentrated sulfuric acid and phosphoric acid
Thread Content
Dear sea friends, based on my personal experience, I would like to share a solution for measuring the flow rates of phosphoric acid and concentrated sulfuric acid in fertilizer plants! Concentrated sulfuric acid generally does not form scabs; it has a high concentration and high viscosity, so cast iron pipes are usually used for its transportation. As it is a pure substance, a Coriolis external ultrasonic flow meter can be considered for measurement. Given the low flow rate and small pipe size, the flow meters used for such measurements typically have a capacity of 0.25–0.30 m3/h, and they offer high measurement accuracy ； Although concentrated phosphoric acid is also a pure substance, it forms scum, which leads to impurities and the presence of particles. Moreover, scum usually forms on the inner walls of pipes, and flow meters based on the differential method cannot detect this. I used a non-Mettler Doppler flow meter for measurement, and the results were excellent! I hope this can be helpful to everyone!
For external clamping ultrasonic devices, there’s no point talking about high precision; it’s sufficient as long as the readings are stable. The accuracy of external clamping types is greatly affected by the medium, pipe material, and pipe conditions; talking about accuracy in such cases is nothing but nonsense.
Since you know so much about this, may I ask you: once a factory facility has been built, how can flow be monitored? There is an electromagnetic flowmeter on site; do you think this flowmeter is very accurate? Currently, the accuracy of imported flow meters can reach 0.5%. Portable clamp-on flow meters represent a mature market with great potential for application. So, expert, if you have any valuable suggestions, please just say them directly. There’s no need to talk about who is being unreasonable. Currently, there are many brands of external ultrasonic flowmeters, as well as many users; I’m not sure whom you mean by those who are being unreasonable And the certificates are issued by the Metrology Institute and the metrology institutes in various provinces and cities – does that mean these institutions are being dishonest or covering up something?
For flow monitoring at the process control level, whether you use an external ultrasonic sensor or an electromagnetic flowmeter, I have no objections – after all, it’s just a matter of reading a number; as long as that number changes along with the valve’s operation, that’s fine. But have you seen any meter-grade measurement using an external ultrasonic gauge? I’ve already mentioned the limitations of external clamped ultrasonic sensors: they are greatly affected by the conditions of the pipes and the medium. How can you ensure that the position of the probe is exactly correct? How can we talk about high precision in such a situation? As for the certificates issued by the metrology institute, are there any professionals with Chinese characteristics who don’t understand them? Select a few good points from the calibration results ； For low flow rates, the high flow rate correction factor must be specified first; only after that can the high flow rate be entered. All of the above are things I have encountered myself. Simply put, every time I go to the calibration institute, there are tons of instruments to be tested, including various types of electromagnetic, differential pressure, turbine, vortex flow meter, and mass flow meter ultrasonic devices; but I’ve never seen any ultrasonic devices of the external clamping type that need to be tested. The reason for this is easy to understand, right?
Hello, expert. Which department are you in charge of working with regarding the measurement system?
Why not use an electromagnetic flowmeter with a lining? The electrode material can be HC or tantalum.
There is an electromagnetic flowmeter on site; I’ve forgotten the specific brand. However, due to the high viscosity of concentrated sulfuric acid and the problem of scaling in concentrated phosphoric acid, the electromagnetic flowmeter is unable to provide accurate measurements