4 replies to this topic

[aanita]

please help me to convert from Nm3 to SCF(Standard Cu. Ft) of any gas mixture.

 

thank you.

[Art Montemayor]

You have to define what you mean by "standard" conditions first before anyone can attempt to obtain your conversion.

 

Be specific.  There must be a couple of hundred definitions around the world by now as to what constitutes "standard conditions".

[chocobang]

Hi Aanita,

 

Art is definitely right, there are many definitions depending on the institution (https://en.wikipedia...re_and_pressure).

 

For EPCM, the normal condition is 0 degC while standard at 15.6 degC (both are at atmospheric condition).

 

Therefore, converting (assuming ideal gas):

 

Nm3 * ((273+15.56)/273) (1/0.3048)^3 = SCF

[Saml]

I will double on Art Montemayor point. It cannot be stated for "any" gas whithout being specific about the context

 

 

Take, as an example the NIST recommendation that for Oxigen, Nitrogen, Argon, Helium and Hydrogen the reference is 70F and 101325 Pa or 14.696 psi

 

https://www.nist.gov...note-1079-2.pdf

 

In OSHA and DOT regulation defines SCF as 60F and 101.3 kPa. May be a rounding from 101.325... or not... if your are invoicing someone, they will observe this rounding.

 

Now, move north and you will find a regulation that says...

 

http://laws-lois.jus...1/FullText.html

standard pressure means

• (a) in the International system of units, an absolute pressure equal to 101.325 kPa, and

• ( in the Imperial system of units,

  • (i) 14.73 psia, or

  • (ii) 30 in. of mercury at 32°F; (pression normale)

 

standard temperature means a temperature that is equal to

• (a) 15°C in the International system of units, or

• ( 60°F in the Imperial system of units; (température normale)

 

Now, move south, and you get

 

http://base.energia....conversion.aspx

• Pies cúbicos a 60°F (15.6°C) y 14.73 psia, y
• Metros cúbicos a 15°C y 101.325 kPa

 

In many places "Normal" for cubic meter means 0°C  and 101325 Pa (is the most common), but it may mean other temperatures (0°C, 15°C, 25°C) and other pressures (760 mmHg, 101325 Pa, 100000Pa, 1Kgf/cm2)

 

And "standard" is the same. I also happen to work in a place where a "standard" cubic meter of natural gas actually means 9300 Kcal of Higher Heating Value independently of the volume it occupies at the standard condition.

[aanita]

You have to define what you mean by "standard" conditions first before anyone can attempt to obtain your conversion.

 

Be specific.  There must be a couple of hundred definitions around the world by now as to what constitutes "standard conditions".

 

SCF to mean standard cu ft (at 15.6 deg C and atm pressure).

Thank you very much Mr. Art and all of you for your time.

Edited by aanita, 04 May 2018 - 01:11 AM.