Issues regarding the measurement of gas density by mass flow meters
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For a pipeline carrying a mixture of phosgene and CO, can the mass flow meter installed on the pipeline accurately measure the density of this mixture? The diameter of the pipeline is DN150, while the diameter of the flow meter is DN80; there are 150 mm diameter reductions before and after the flow meter. In such a situation, is it possible for the mass flow meter to provide an accurate measurement of the fluid density? Could changes in pipe diameter lead to inaccurate density measurements?
Measuring density is no problem; the change in diameter has no impact.
It seems that a certain length of straight pipe section is required. Check the instructions specifically.
Yes, the required lengths of the straight sections before and after each type of flow meter are different.
As long as the straight pipe section meets the requirements, there will be no problem. I’m just curious, why are you measuring the density? This phosgene + CO must be produced through the synthesis of phosgene, right? Are there mass flow meters for chlorine and CO ahead? When you adjust the molar ratio, this density will also change
I consulted the manufacturer, and they said that Coriolis mass flowmeters have no requirements regarding the length of the straight sections before and after them
For compressible fluids like gases, isn’t measuring density inaccurate?
That is, the purity of phosgene is estimated to be 1 based on the molar ratio, while it is determined to be 2 through density calculation using the flow meter in the phosgene pipeline; there is a significant difference between purity 1 and purity 2. I then consulted the flow meter manufacturer, and I was told that mass flow meters inherently suffer from significant errors when measuring gas density.
There should be a chlorine analyzer for free chlorine in phosgene behind the phosgene reactor; a level of less than 50 ppm is sufficient. . . By adjusting the molar ratio, the purity of phosgene can be controlled, right? The mass flow meter at the back seems redundant
Generally speaking, as long as the diameter change is within the allowed range, the impact of precision can be practically ignored
Mass flow meters have no requirements regarding straight pipe sections for installation, as they do not need to stabilize the flow of the medium. Those who claim that a straight pipe section is required for mass flow meters do not understand the measurement principle of such meters.