LPGLPGLPGLPGTO CALCULATE THE WEIGHT OF LPG VAPOURS

IntroductionIntroduction IntroductionIntroduction

The LPG vapour calculation is quite simple and the formula is based on the following laws:

Gay Lussac’s Law:Gay Lussac’s Law:Gay Lussac’s Law:Gay Lussac’s Law:

The density of a gas at standard temperature and pressure is proportional to its molecular weight.

Charles’s Law:Charles’s Law: Charles’s Law:Charles’s Law: The volume of a given mass of gas is

directly proportional to the absolute temperature, provided the pressure remains constant. If the formula is transposed, it can be deduced that the density of a given mass of gas varies inversely with the absolute temperature provided the pressure remains constant.

Boyle’s LawBoyle’s Law::The volume of a given mass of

gas is inversely proportional to its pressure, provided the temperature remains constant (or density varies with the absolute pressure, provided the temprature remains constant).

1/22,400 is half the density of hydrogen (H2) which gives the theoretical density of 1 cubic meter of H (as opposed to H2) – the simplest and lightest atom.

Written for a fixed temperature, theindividual effects of these laws are;

Gay Lussac’s Law = Density varies with molecular weight of the vapour.

Charle’s Law = Density varies inversely with absloute temperature.

Boyle’s Law = Density varies with absloute temperature.

1/22,400 = A constant

The conclusion derived from the three lawscan be combined to give the formula for Vapour Density as;

273/273+Tvap x1.033+Pvap/1.033 x Mol. Wt/22,414

Vap. Mass = Vap. Volume x Vap. DensityVap. Weight = Vap. Mass x *W.C.F. (T-56) *W.C.F. = Weight Correction Factor for conversion of Mass

into Weight (M/Tons in Air)