# Chemical Forums

## Specialty Chemistry Forums => Chemical Engineering Forum => Topic started by: sania on July 07, 2007, 07:24:12 AM

Title: Normal Cubic Meter of Gas
Post by: sania on July 07, 2007, 07:24:12 AM
I read in gas processing industry the term Normal Cubic meter is used (Nm3) of gas,From normal i got an idea that normal means
A Normal Cubic Meter of a gas (Nm3) is the volume of that gas
measured under the standard conditions of 0 degrees Celsius,
and 1 atmosphere of pressure. As volume of a gas is inversely proportional to its pressure, and proportional to absolute temperature. How can we convert it in to room or process temperature. By using pv = nrt or some other method. how can we find the volume of gas. Want a detail answer from you. Thankyou
with kind regards
Title: Re: Normal Cubic Meter of Gas
Post by: Borek on July 07, 2007, 07:28:53 AM
PV = nRT will do.
Title: Re: Normal Cubic Meter of Gas
Post by: sania on July 07, 2007, 10:36:43 AM
One more thing where we use Compressibility factor in PV=nRT. I mean in which condition we use Z1 and Z2. Thankyou
With kind regards
Title: Re: Normal Cubic Meter of Gas
Post by: Montemayor on July 10, 2007, 12:38:30 PM
Sania:

I understand you to say that you know the “Normal” volume of a gas and want to know the actual volume at a specific temperature and pressure (both different from “Normal” conditions).  If that is what you mean, then you can use the Ideal Gas Equation PV = nRT – but only if you know the molecular weight of the gas.  A more conventional method of converting the volume is to use the result of combing simultaneous equations:

V2 = V1 (Z2/Z1) (P1/P2) (T2/T1)

Where,
V2 = gas volume at the new condition, m3;
V1 = “Normal” gas volume, m3;
P1 = 1.0 atm, absolute;
P2 = pressure at the new condition, atm., absolute;
T1 = 273 oK;
T2 = absolute temperature at new condition, oK.

The above equation is derived dividing one of the following equations by the other:

P2 V2 = Z2 n R T2
P1 V1 = Z1 n R T1

I hope this helps you out.
Title: Re: Normal Cubic Meter of Gas
Post by: mbeychok on August 08, 2007, 05:09:22 PM
Sania:

Art Montemayor's equation is perfectly correct.

But I would caution you on assuming that Normal conditions are always 0 degrees Celsius and 1 atmosphere. There is no universally accepted set of Standard or Normal temperature and pressure conditions.  I urge you to read this article:

http://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressure

For example, as  you will see in the above article, the International Union of Pure and Applied Chemistry (IUPAC) defines the standard conditions of temperature and pressure as 0 degrees Celsius and 100 kPa which is 1 bar (not 1 atmosphere) and has done so for a good many years.
Title: Re: Normal Cubic Meter of Gas
Post by: technologist on August 27, 2007, 06:21:29 AM
U can also refer my post

http://profmaster.blogspot.com/2007/07/suction-vs-discharge-gas-flow.html (http://profmaster.blogspot.com/2007/07/suction-vs-discharge-gas-flow.html)