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Gas Density - Nitrogen

Gas Density - Nitrogen

Gas Density - Nitrogen

(OP)
Hi there guys,

I know this is the right forum for this question and I believe too mostly are working on process engineering. This question could be very simple for you but it took me a while to figure it out simply becuase of the metric unit I'm not use to. I have a system running on compressed nitrogen gas at 1650 psig and 150 deg F. Using ideal gas equation, density = p/RT where p is the operating pressure in lbm/cu. ft., R is specific gas constant equal to .2968 Kj/Kg-K from my research, and T is the temp at deg R. Since R has to be in consistent unit of ft-lbf/lbm-degR, I managed to convert the specific gas constant R in metric to customary english units and I am getting 3.8 lb/cu ft. To those who are more orineted in this kind of job, please correct me or kindly validate this calculation. Thanks a lot for all of your help or hints on this issue.

Regards,

RE: Gas Density - Nitrogen

Phil,

I believe you have made a mistake somewhere, but your formula is correct.  The numbers I get are

P = 1650 psig = 239717 lbf/ft2 absolute
R = 55.191 ft.lbf/lb.R
T = 150 deg F = 609.7 deg R

Density = 1/V = 239717 / (55.191 x 609.7) = 7.12 lb/ft3

This is a very error prone process because of all the conversions. I have written a calculator that does it all for you.  You can download Uconeer from www.katmarsoftware.com for free and the gas density calculator is part of the gas flowrate convertor (click the fan icon to run).

Harvey

Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com

RE: Gas Density - Nitrogen

(OP)
Hi there Harvey,

We'll sure you are absolutely right. My pressur is in gauge and I need to add 14.7 to make it absolute. I'll surely download your software and I'll visit your software homepage too. Thanks a lot for your quick help.

Regards,

Phil

RE: Gas Density - Nitrogen


The value from the NIST tables is 6.92 lb/cuft.

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