Propane from tanks

G’day; I use fairly small propane tanks for jewellery, so I
have always got some. But let me tell you a story: there is a
snag. We have wells in NZ which produce gas and oil; also
refineries to make all sorts of things from the liquid WE call
petrol to fuel our autos, to a fertiliser called urea. The natural
gas they produce is reticulated to the towns in the North Island;
(the South Island where I live misses out as the Cook Strait
between is too turbulent for a pipeline) The domestic gas is
mainly propane. They also bottle a gas into cylinders (or tanks)
which they sell as propane, but it also contains butane which is
a rather unwanted side product of the refining process. So,
what do they do to make more money? Why, increase the amount of
butane in the mix, a ‘good’ way of getting rid of it, eh?
Unfortunately liquid propane has a lower boiling point than
butane so after a while, your gas tank contains mostly butane,
(the propane having boiled off first.) Butane has a much lower
heating value and a much lower flame propagation rate so that it
becomes very difficult indeed to keep alight the torches one uses
for needle point flames for fine work, and the flame isn’t hot
enough anyway. So what can we do? Put the gas tank outside with
the biggest burner we’ve got, and (safely) burn away the butane
before we get the tank refilled. Waste of time, money and
resources. Bit of a bummer, eh? Does the same sort of ripoff
happen in your country? We just grin and put up with it. :-[

   / /    John Burgess, 
  / /
 / //\    @John_Burgess2
/ / \ \

/ (___)