Re: [A/S] Another Propane Cylinder question

[Jerry Flanders <jflanders2@xxxxxxxx>]

More on LPG than you wanted to know:

The industry info tells us that we are not buying propane, we are buying 
"LP gas".

They also tell us: "LP Gas is a mixture of light hydrocarbons which are 
gaseous at normal temperatures and pressures. Being odorless, for safety 
reasons, a pungent compound ethyl mercaptan is added to make any leaks 
easily detectable."


                 Boils   Freezes
Propane       -49      -306
Butane          31      -216

(degrees F, at atmospheric pressure)

Butane has about 10% more energy per gallon, but about the same energy per 
pound (it is denser).

Above is from industry info. This is from me: I remember my Chemistry prof 
telling us that the mix of B/P (with bits of other stuff like Ethane and 
Pentane thrown in - it isn't ever _completely_ pure, because refineries 
don't operate that way) we get depends on where in the country we live and 
the temp range expected soon. (Gasoline blends change similarly to make 
sure your car starts easily when cold). Those of us in the south will get 
more butane in our LPG than you yankees. Years ago I remember friends had 
problems with their furnaces in very cold weather - the LPG wouldn't flow 
at really low temps (see above - no Butane "pressure" at 31 F) - I realize 
now they had mostly Butane in their tank (maybe leftover from earlier in 
the season).

Jerry Flanders (retired Chemist)