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Propane Gas Volume to Liquid Volume conversion

Propane Gas Volume to Liquid Volume conversion

Propane Gas Volume to Liquid Volume conversion

(OP)
hello all, i am trying to convert a gas flowrate of propane to equivalent liquid volume and mass.


My consumption of propane is at 0.5 mmscfd. I have tried to do following calculation by converting gas propane to mass and then using that mass and liquid density to convert to liquid volume,. Can any experts take a review and see if this calculation looks good. or if there is any mistake


Propane Consumption = 0.5 MMSCFD= 0.5 x 10^6 / 24 = 20833 scfh

This is at 100 psig and 65°F

I convert this standard flow to actual flow using ideal gas law

Tact = 65 F = 460 + 65 = 525°R

Pact = 100 psig = 100 + 14.7 = 114.7 psia

Tstd = 60 F = 460 + 60 = 520°R

Pstd = 14.7 psia

R = 10.73 ft3 psi / lbmol °R

Pact Vact / Tact = Pstd Vstd / Tstd

Vact = Pstd Vstd / Tstd x Tact/Pact

Vact = 14.7 x 20833 / 520 x 525/114.7

Vact = 2965 ACFH

Number of moles of Propane can be found by PV = nRT

n = PV / RT

n = 114.7 x 2695 / 10.73 x 525 = 54.86 lbmol/h

Propane Mol Wt = 44.1 lb/lbmol

Propane Mass Consumption = 54.86 x 44.1 lb/h = 2419 lb/h (gas mass = liquid mass; mass conservation)

Propane Liquid Density at ambient conditions (80F ) = 30.58 lb/ft3

Propane Liquid Volume Consumption = 2419/30.58 = 79 ft3/h

RE: Propane Gas Volume to Liquid Volume conversion

I only went so far as to say that "standard flow" is equivalent to a mass flow, so your effort to convert to "actual flow" is misguided. Standard flow is the information you need for further calculation, and you already have that to start with.

RE: Propane Gas Volume to Liquid Volume conversion

(OP)
Calculating for the mass flow from standard flow will give the same value using gas law. So what exactly do you mean by misguided?

RE: Propane Gas Volume to Liquid Volume conversion

Your calc is correct, and you have gone the long way to compute the liq vol consumption. A shorter way is as compositepro suggested. Use whatever method makes sense to you.

RE: Propane Gas Volume to Liquid Volume conversion

There are 359.38 scf/lb-mole.

20833 scf/hr / 359.38 scf/lb-mole
= 57.969 lb-moles/hr

57.969 lb-moles/hr x 44.097 lb/lb-mole
= 2556.3 lb/hr

Liquid propane at 77 °F is 4.11 lb/gal.

2556.3 lb/hr / 4.11 lb/gal = 622 gal/hr

Your way is correct, just inefficient.

Don't worry, when you have done these for 45 years like me, you'll get more efficient.

Good Luck,
Latexman

RE: Propane Gas Volume to Liquid Volume conversion

(OP)
@kkengaged - what are the units in your calculation? 113.7 -- ? , 30,669 ---- ? What is meant by dividing uncompressed measure of propane by 1000??

How can we apply this 1:270 rule to 0.5 mmscfd of propane vapor ??? to get the equivalent liquid?

RE: Propane Gas Volume to Liquid Volume conversion

Zamakaze,

He's talking rubbish just so he can get his advert in. It's been red flagged.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Propane Gas Volume to Liquid Volume conversion

(OP)
@LittleInch - Thank you

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