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Different mixtures of Propane


#1

Somebody posted to a list that I’m on that their propane dealer told
them there were different “mixtures” of propane for different
applications.

I live where we heat with delivered propane, and this is the first
I’ve ever heard about “different mixtures of propane”. Propane is
propane is propane, as far as I know, and my dealer and I were
planning on having me use the same propane for my torch (when I get
it) that I use for heating.

So what’s the skinny? ARE there different “flavors” of propane, or is
somebody just selling a bill of goods?

Sojourner


#2

propane used for road use (some cars or trucks) is taxed bar b que or
weed burners is not taxed also home use for heating,

Don in Idaho


#3

I am no propane expert but I do know that propane is a direct
product of petroleum refining. When they start breaking down the
hydrocarbons into their various components, propane is one of them.

Brian


#4

G’day.
The NZ plant at Motupipi on the West Coast of the North Island
processes oil from the local well in Taranaki into a number of
things, ethane, methane propane and butane etc. (even urea). But in
processing for propane more butane is made than sales demand, so the
propane we get in the usual containers is invariably mixed with
butane.

As butane has a higher boiling or evaporation temperature, the tanks
tend to end with almost all butane at the bottom, when used for
jewellery. But butane doesn’t burn so nicely at the air-propane gas
mixture that jeweller’s torches use, and I find I often have to
waste the last bit of gas in the container. And it is quite a bit
sometimes.

It is also used to drive motor vehicles, and most fuelling stations
sell it. So, if you don’t like it you can go down the road - and
get exactly the same stuff from the next station. If you don’t like
that, you are welcome to do the other thing!! She’ll be right,
mate as they say in NZ.

Cheers for now,
JohnB of Mapua, Nelson NZ


#5

I’ve discovered a few interesting things over the years. Here in New
Zealand the ‘propane’ sold for use in cars (LPG) is a mix of propane
and butane, the percentages vary by brand, but roughly 60/40.

I believe the butane in the mixture tends to stratify (down) if the
tank is left standing. Naturally in an automobile the tank gets a
good old shake about. However for jewellery use the stratification
could be a problem so that towards the end of the bottle you may be
burning butane, and butane’s also reputed to be harder to ignight as
a torch gas in the colder months.

Another problem associated with the mixture emerged. Over the years
we’ve noticed that our torch heat-colouring of titanium becoming more
and more erratic, with spots appearing where we didn’t want them.
After theknee-jerk reaction that is was Ractive Metal’s metal, we
investigated the gas in our bottles. Turns out that the butane % in
our local gas was increasing! I found a source in Auckland of 96%
propane LPG, and use that bottle for heat-colouring.

  Why are Butane and Propane used in combination? While butane
  and propane are different chemical compounds, their properties
  are similar enough to be useful in mixtures. Butane and Propane
  are both saturated hydrocarbons. They do not react with other.
  Butane is less volatile and boils at 0.6 deg C. Propane is more
  volatile and boils at - 42 deg C. Both products are liquids at
  atmospheric pressure when cooled to temperatures lower than
  their boiling points. Vaporization is rapid at temperatures
  above the boiling points. The calorific (heat) values of both
  are almost equal. Both are thus mixed together to attain the
  vapor pressure that is required by the end user and depending on
  the ambient conditions. If the ambient temperature is very low
  propane is preferred to achieve higher vapor pressure at the
  given temperature. 
  http://www.e-lpg.com/lp_gas.asp. 

Brian

B r i a n A d a m
e y e g l a s s e s j e w e l l e r y
Auckland NEW ZEALAND
www.adam.co.nz


#6

Different mixtures in Propane are obtained when the petroleum is
separated into differing factions by a form of distillation . The
basic distinctions are in the number of carbon atoms in a straight
chain. This determines the boiling point.

(1) Methane, (3) Propane, (4) Butane, (8) Octane are used as
standards for comparison. Natural Gas is mostly Methane. Propane
and Butane are used as bottle gas fuels. and Octane is used as
liquid automobile fuel. HPNG is bottled Methane, high pressure
natural gas , a good fuel, but hard to find. It comes in a heavy,
thick wall tank like Oxygen, or Hydrogen Butane is used more in
warmer environments because it has a higher boiling point and lower
pressure at higher temperatures than Propane

So - your fuel is primarily propane with other factions mixed in.
This is because of manufacturing and distribution economics. Both
combust well. Unless You find a problem, don’t bother looking for
one.

Robb.