Total LPG Mass in tank 1

[harrypapas]

How do i go about calculating the total mass of LPG (mixture butane-propane)in a tank which contains both liquid and gas phases.
Given data are: Total tank volume, liquid level, total pressure and tank temperature.

Any input will be appreciated.

Harry

 

[BigInch]

Get the mixture percentages from this chart, given the tank temperature and pressure,

http://www.engineeringtoolbox.com/propane-butane-mix-d_1043.html

Find the densities of propane and butane liquid at the same temperature and pressure and multiply each by the percentage in the mix.

If the level was relatively high, I'd tend to just ignore the mass of the gas phase.

"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.

"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

 

[25362]

If you are after the gas and liquid compositions, then a bubble point calculation using K values may be of help.

See also thread135-111334.

 

[25362]

Or use Raoult's law since the negative deviations would be minor.

 

[dcasto]

((LIQUID sggr -((temp-60) * .0015)) * 62.4 * % tank liquid level * + (100%- % liquid level) * Vapor SPGR *.0765 * Press in absolute/14.696 * 520/ temp absolute) * volume in Ft^3

 

[harrypapas]

Thank you dcasto. Please clarify few things on the equation you posted
What are: sggr and spgr
I see that the equation is not temp consistent. Both F and R are used. Is this correct?
Is volume (last term in equation) the tank volume?

Harry

 

[dcasto]

the sggr is suppose to be spgr. spgr is specific gravity of the fluid. Propane and butane liquid spgr will run from .51 to .65 depending on mixture and the vapour spgr will run beteen 1.6 and 2.0 again depending on the mixture %.