How to calculate the quantity of cubic meters of gas evaporated from 1 liter of liquefied gas? Does the formula change when you use «winter» or «summer» mixture?

(pic. 105.1 – Gas expansion during warming up)

(pic. 105.2 – How to calculate the quantity
of cubic meters of gas?)

Knowing the density and quantity of liquefied gas in liters it’s possible to calculate the volume of evaporated gas in cubic meters. But this figure will be approximate because the density of liquefied petroleum gas (LPG) depends on temperature and composition of propane-butane mixture. «Winter» and «summer» gases have different density and different boiling temperature.

The only one constant value is weight of liquefied gas: temperature increase provides gas expansion, lowering of temperature provides gas loading. The higher outside temperature the bigger gas volume. And conversely.

That is why the volume of evaporated LPG will significantly different in winter and in summer. There is no any sense to calculate the volume of gas in cubic meters. Considering this indicated gas flow rate is taken in kilograms which are similar in winter and in summer.

In case you would like to exercise with figures here you’ll find calculating formulas:
 

• Density of propane in gas phase (l/m3) = Density of propane in gas phase (kg/m3)/Density of propane in liquid phase (kg/l).
  
  
• Density of butane in gas phase (l/m3) = Density of butane on gas phase (kg/m3)/ Density of butane on liquid phase (kg/l).
  
  
• For «winter» gas: Density of propane and butane mixture in gas phase (l/m3) = Density of propane in gas phase (l/m3)*0,75 (75% of propane in mixture) + Density of butane in gas phase (l/m3) * 0,25 (25% of butane in mixture)
  
  
• For «summer» gas: Density of propane and butane mixture in gas phase (l/m3) = Density of propane in gas phase (l/m3)*0,45 (45% of propane in mixture) + Density of butane in gas phase (l/m3)*0,55 (55% of butane in mixture).

Don’t forget that the density of liquid and gas phases depends on temperature, so, the result will change.
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