Friday, Sep 25, 2009 at 13:09
Gas aint gas.
Autogas = Propane/Butane mix
In most
places in Australia, Auto gas is a blend of Propane and Butane. Because of the different “weights” of these gasses, they “boil” off at different temperatures. This makes no difference in an automotive situation as the gases are draw off the bottle in a liquid form, and “boiled” in a heat exchanger under the bonnet to a gaseous form to burn in the engine. In Northern Australia, far from refineries, Auto gas and Bottle gas usually are the same thing, Propane, as it is un economic to ship two different gasses by sea for the small quantities used of either one on its own.
LPG (Liquified Petroleum Gas) = Propane
In a bottled gas for
home heating/cooking it is an entirely different kettle of fish. As the gas is drawn off the bottle In a gaseous form, the lighter of the two gasses (Butane) boils off first due to its lower boiling point, then the heavier gas (Propane) boils off after all the butane has gone. These two gasses need different jetting / controls as they have different calorific values, creating different heat for the amount of gas burnt.
Propane and Butane can be maintained in a liquid for by being stored under moderate pressure.
That is why
home heating/cooking gas is supposed to be pure propane only.
Natural Gas = Methane
Natural gas is Methane, which is lighter again that either Butane or Propane, actually lighter that air, where as Butane and Propane are heavier than air. Methane needs different jetting and controls as its calorific value is different yet again.
Methane cannot be stored as a liquid under pressure, as the pressures required are so high, that it is uneconomic to do so. Pressure vessels become too heavy to move, and build. Methane however lends itself to storage as a liquid under refrigeration, and is stored as a cryogenic liquid at about -270 deg centigrade. This then can be stored in light weight containers, with adequate insulation, and maintains liquid form by slowing boiling off as it absorbs heat. (Blood big eskies)
It is true that all these gasses come from a hole in the ground, but are separated in large refrigerated gas chains to purify them for their intended uses. Also from this same hole in the ground are extracted Carbon DiOxide, Helium, Nitrogen, and various sulfur compound gasses. Propane and Butane also are derived from Light crude oil refraction and distillation and used to be an oil refinery waste produce many year ago.
So, Gasses anit Gasses.
FollowupID:
652356