Regarding the conversion of volume flow and mass flow (more urgent)
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The design document gives a mass flow rate. Now our DCS requires a volume flow rate (hydrogen). For example, given the mass flow rate of 278.2KG/H, and the following data) (I don’t know which one can be used), what is the volume flow rate M3N/H? MOLE FLOW, KG MOLE/E 115.32 MOLE WEIGHT, KG/KG MOLE 442.5 LIQ VOL FLOW,STD M3/H 0 LIQ DENSITY,KG/M3 0 VAP DENSITY, KG/STD M3 0.17 This post was last edited by che7418 on 2009-2-5 01:01 ]
The mass flow rate divided by the density at that temperature is the volume flow rate
278.2/0.17=1636 STD M3 /H
It should be the bottom number, 0.17, or you can check the manual to find the density of hydrogen.
I really didn’t expect that such a simple formula would work. I thought I had to operate things like pressure and temperature. Thank you very much. It's a small problem, but it helped a lot.
If you want to calculate the standard volumetric flow rate, then confirm that the operating pressure and temperature are required. 278.2/0.17=1636 STD M3 /H The volume flow calculated by this formula is only the volume flow under the operating pressure and temperature, not the standard volume flow (Nm3/h).
I think the formula 278.2/0.17=1636 STD M3 /H calculates the volume flow rate under standard conditions.
From the perspective of precise control, this conversion is not completely accurate. The VAP DENSITY, KG/STD M3 0.17 it gives should refer to the design conditions, which must be very different from the actual working conditions. The temperature and pressure should still be corrected, otherwise the calculated volume flow rate will be inaccurate.
The mass flow rate is known, and if it is pure hydrogen, the molecular weight is known, then the molar flow rate is found, and then multiplied by 22.37, the standard volume flow rate can be obtained. 278.2/2=139.1 The standard volume flow rate is: 139.1 * 22.37=3111.667NM3/H
Gases are compressible, be careful to use mass flow = volume flow/density. It can also be calculated by limiting the maximum flow rate of the gas in the pipe. The flow rate of hydrogen is 15M/S. * The density is high, but it is safe.
I agree with the statement on the 7th floor because the standard volume flow rate means: the volume flow rate under standard temperature and pressure conditions. What is calculated in this way is the volume flow rate under the pressure and temperature. You need to look up the table and do the calculation to get the result.