Is Propane the Same as LPG – Butane vs Propane

Is Propane the Same as LPG? Propane is LPG but not all LPG is propane. LPG – Liquefied Petroleum Gas – is flammable hydrocarbon gas liquefied through pressurization. Butane vs Propane: Butane and propane are both LPG gases. LPG comes from natural gas processing and oil refining. Propane is classified as LPG, along with butane, isobutane and mixtures of these gases.

LPG is frequently used for fuel in heating, cooking, hot water and vehicles.

Difference Between Butane vs Propane

The difference in boiling temperature means that propane performs much better in cold weather, as butane stops working below freezing.

The lower pressures generated by butane make it more popular as an aerosol propellant.

The difference in specific gravity means that butane weighs about 14% more for any given volume.

These differences and others are shown in the table of properties below:

Butane vs Propane Properties

Gas Properties	Butane	Propane
Chemical Formula	C4H10	C3H8
Energy Content: MJ/m3	111.4	95.8
Energy Content: MJ/kg	47.39	49.58
Energy Content: MJ/L	27.5	25.3
Boiling Temp: Cº	-0.4	-42
Pressure @ 21ºC: kPa	215.1	858.7
Flame Temp: Cº	1970	1967
Expansion: m3/L	0.235	0.270
Gas Volume: m3/kg	0.405	0.540
Relative Density: H2O	0.58	0.51
Relative Density: air	2.00	1.53
L per kg	1.724	1.96
kg per L	0.58	0.51
Specific Gravity @ 25ºC	2.07	1.55
Density @ 15ºC: kg/m3	2.544	1.899

 

Many of the gas appliances sold in Australia are manufactured overseas.

 

So, you get it home, open the box, start to read the owner’s manual and there it is!

 

It says that the appliance is made for use with Propane.

 

But where do you buy Propane in Australia?

 

The bad news is that this causes a lot of confusion and concern.

 

The good news is that propane is readily available in Australia, we just call it LPG.

 

Propane is LPG, so no worries!

 

Propane is the gas that is supplied to virtually all homes and most businesses that purchase LPG in Australia.

 

It is supplied in gas bottles that are either exchanged or refilled on site by tankers.

 

 

These are typically 9kg bottles.  SWAP’n’GO BBQ gas bottles are a good example of a swap system.

 

In Australia, LPG goes by a number of names including LPG, LPG gas, bottled gas, Propane, BBQ gas, camping gas and LP gas, so it can be quite confusing.

However, it’s all the same gas.

 

7 Important LPG Facts

1. LPG is the acronym for Liquefied Petroleum Gas or Liquid Petroleum Gas.

2. LPG is a group of flammable hydrocarbon gases, including propane and butane, that are liquefied through pressurisation and commonly used as fuel.

3. It comes from natural gas processing and petroleum refining.

4. There are a number of gases that fall under the “LPG” label, including propane, butane and isobutane (i-butane), as well as mixtures of these gases.

5. These gases can all be compressed into liquid at relatively low pressures.

6. It is frequently used for fuel in heating, cooking, hot water and vehicles, as well as for refrigerants, aerosol propellants and petrochemical feedstock.

7. It is generally stored, as a liquid, in steel vessels ranging from small BBQ gas bottles to larger gas cylinders and storage tanks.

 

LPG, which is propane, is not to be confused with Natural Gas, which is primarily Methane.

When Natural Gas is initially extracted from the ground it may also contain Ethane, Propane, Butane, Pentane and

Pentanes Plus.

Most of these are usually stripped out for other specific applications before the natural gas is passed along through the pipelines.

Impurities are also removed, including water and Sulphur.

The chemical formula for Methane is CH₄ (Methane molecule model shown).

How Do Propane and Butane Work?

Propane and butane are stored under pressure, as a liquid, in a gas bottle.

It turns back into gas vapour when you release some of the pressure in the gas bottle by turning on your gas appliance.

Almost all of the uses for them involve the use of the gas vapour, not the liquefied gas.

What are Propane and Butane Used For?

They have hundreds, if not thousands, of uses.

The uses most people can name are around the home, in their cars or for business.

It is used in leisure time activities including caravans, boats, recreational vehicles, hot air balloons and camping.

Business and industry use them for a multitude of processes including steam boilers, kilns, ovens and gas forklifts.

Crop and produce drying, heating greenhouses, hot water for dairies, irrigation pumps and heating animal enclosures are just some of the agricultural applications.

There are also many, many more applications, including autogas, power generation and the hospitality industry.

In Australia, we are lucky that we use Propane because it has some advantages over Butane. (Propane molecule model shown)

The most important advantage is that Propane works better in cold weather. as previously mentioned.

It is a liquid under pressure in the gas bottle.

It turns to vapour when you turn on the appliance and relieve some of the pressure, but only if it is above its boiling point.

Propane boils at around -42°C, so it would need to be really cold for it to not vapourise.

Butane, on the other hand, boils at about  -1°C, so you could wake up on a cold winter morning with no working gas.

No fun at all!

And Then There is Butane

The exception to the rule is “autogas”, which is what you buy at the servo for your gas powered car.

Autogas can be pure Propane or it can be a mixture or Propane and Butane.

Either should work equally well, as the Propane component is typically 60% or more.