Re: [A/S] Another Propane Cylinder question

["Mr. Joy H. Hansen" <joytbrew@xxxxxxxxxxx>]

Hi Tom,

I hope the displace thing was a tongue in cheek comment! :)  As you know,
the first thing that happens to a new tank is the purging (typically at an
added cost to the refill in many areas) to displace much of the air - liquid
propane in, air and etc. out!

Hope everyone realizes that the stuff in the propane tank can exist in three
phases at once, depending on the temperature. (Typically, the propane is
pumped as a liquid into the destination tanks.) There can be frozen propane,
liquid propane, and gaseous propane.  Anything in the gas phase will be a
mixture of all impurities that can vaporize - something to do with partial
pressures.  e.g. The operation of the typical Airstream refrigerator with
gaseous ammonia, hydrogen, ammonia dissolved in water and the partial
pressures thereof!

Anyway, it's unlikely that there's any water in the tank due to the nature
of purging, filling, etc. with a propane tank.  There is, to be sure
non-volatile components that could be considered as pumping oils, etc. that
enter the tank with the propane.  Unfortunately, acids and other corrosives
could be present in the liquid propane being pumped into the destination
tank.  Think of all the impurities that can enter the system from the hoses,
mechanical pumps, low temperature lubricants, valves, etc.  Guess some
metals could cause electrolysis inside the tank, especially where aluminum
is concerned.

All this isn't tongue in cheek, but real concerns I would have about propane
tanks.  Especially when they are used for 30 years without certification!

                                                    '69 Safari, Joy