Flow rate of nitrogen from bulk tank into assembly plant
Flow rate of nitrogen from bulk tank into assembly plant
(OP)
I am currently trying to measure the flow rate and/or volume of a low pressure nitrogen line. We use high pressure (3200 psi) and low pressure (150 psi) lines coming from a 3000 gallon liquid nitrogen tank. I am trying to measure the amount of low pressure nitrogen that we use on a monthly basis to determine the cost and possible cost savings. The low pressure comes from the bulk tank, through a vaporizer, into the assembly facility through 3/4" piping at 150 psi and enters the plant at ambient temperature. We use approximately 10,000 gallons of nitrogen per month, including high pressure and low pressure.
I have recently purchased a flow meter that 0-20 SLPM, with 1/8" fittings. I have spoken with representatives constantly to see if this would restrict the flow of the line. I do not see how going from 3/4" to 1/8" over any period of length will not have some effect on the pressure or flow. I have the fittings to put this flow meter in line with the low pressure system, I just do not want to hurt the overall system. Any help on this would also be very appreciated.
Thanks,
DuckCommander
I have recently purchased a flow meter that 0-20 SLPM, with 1/8" fittings. I have spoken with representatives constantly to see if this would restrict the flow of the line. I do not see how going from 3/4" to 1/8" over any period of length will not have some effect on the pressure or flow. I have the fittings to put this flow meter in line with the low pressure system, I just do not want to hurt the overall system. Any help on this would also be very appreciated.
Thanks,
DuckCommander





RE: Flow rate of nitrogen from bulk tank into assembly plant
how much pressure drop are experiencing in the 3/4" line
RE: Flow rate of nitrogen from bulk tank into assembly plant
Good luck,
Latexman
RE: Flow rate of nitrogen from bulk tank into assembly plant
2. Make sure the flow meter is calibrated at the density,pressure, and temperature you are working with. I ran into this with a similar situation where the flow meter was calibrated with air at 14.7 psia and 59 F and the process fluid was nitrogen at 90 psig (104.7 psia) and variable temperatures (see #3). If not, you will have to include a factor to account for these differences.
3. The process temperature from a liquid nitrogen vaporizer is typically 30 F lower than ambient - so the temperature of the gas will vary widely from winter to summer. This must be taken into account with the flow meter calibration.
RE: Flow rate of nitrogen from bulk tank into assembly plant
RE: Flow rate of nitrogen from bulk tank into assembly plant
worse case N2 usage appears to be 60 lbs/hr or so, a rather small flow if it is continuous (24/7) usage, if not then you need to quantify the peak usage.
you can accomplish this in part by performing pressure survey of the installation
regardless of the meter size or type, it is a good idea to provide a block and bypass piping.
you can guage the flow in part if you repeat the pressure survey by partially closing a block valve near the supply point
if the flow is not quantifiable ahead of time, then install a rotameter suited to the pressure for a quick and less expensive measurement.
RE: Flow rate of nitrogen from bulk tank into assembly plant
How is it possible to not already know this? You must get a bill from your N2 supplier.
RE: Flow rate of nitrogen from bulk tank into assembly plant
If you knew you had 3/4" lines, why would you have purchased a 1/8" flow meter?
TTFN
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