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[titim]

Hi everyone, i need an equation between Density at 15 ⁰C in Air and Density at 15 ⁰C in vacuum for petroleum products:

 Density at 15 ⁰C in vacuum = Density at 15 ⁰C in Air + (or - ) A

A: a constant

and which standard talks about it.

thanks a lot

Edited by titim, 14 June 2017 - 06:35 AM.

[MrShorty]

Not sure I understand exactly what you are trying to calculate here. Are the petroleum products liquids or gases at the desired initial and final conditions? How does air figure into the problem?

 

If I assume that "density in air" simply means "density at 15 C and ambient pressure/atmospheric pressure"  (and air really has nothing to do with the question), then I see two basic approaches, depending on whether the petroleum product is gas or liquid:

 

1) If product is a gas, use ideal gas law (or other suitable equation of state) to compute density at initial pressure and at final pressure.

 

2) If product is a liquid, you can use your favorite equation of state to compute density at T and P. You can also lookup the "isothermal compressibility coefficient" or "bulk modulus" for the desired fluid and put that into your isothermal compressibility equation. (https://en.wikipedia...ki/Bulk_modulus )

Of course, if your vacuum pressure is below the saturation pressure of the fluid, then your density change is all in the phase change from liquid to gas.