LPG vs Propane - Is Propane the Same as LPG | LPG Propane

LPG is propane and propane is LPG. Essentially, LPG and propane are the same thing. Liquefied Petroleum Gas (liquid petroleum gas) - LPG or LP gas - is also described as just propane or butane. LPG are flammable hydrocarbon gases used in BBQ gas bottles and as fuel for gas heating, gas hot water, cooking gas cylinder and LPG cars.

Propane (C₃H₈) and Butane (C₄H₁₀) have very similar chemical formulae. Both flammable hydrocarbon gases are considered LPG - Liquefied Petroleum Gas. Whilst propane and butane are both independently LPG, they are unique chemically, being different chemical compounds. Both liquefy under pressure.

The chemical formulae for Propane – C₃H₈ – and Butane – C₄H₁₀ – are both comprised of just carbon and hydrogen atoms, as they are similar flammable hydrocarbons. Propane and Butane, while separate chemicals, are both classified as LPG - Liquefied Petroleum Gas – individually or as a mixture.

Propane (C₃H₈) and Butane (C₄H₁₀) are both flammable hydrocarbon gases with similar or identical formulae categorised as Liquid Petroleum Gas - LPG. Whilst they are different forms of LPG, they are still both LPG. Propane has superior performance in cold weather.

Whilst LPG is either propane, butane or a mixture of the two, they are different chemicals. Autogas is either propane or a propane and butane mix.

Liquefied petroleum gas (LPG or LP gas) is also referred to by its constituent names - propane or butane. In addition to propane, LPG can be butane, isobutane or any of a number of different gases.

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. In the UK, LPG is the same as Calor gas.

However, it’s all the same gas.

LPG are hydrocarbon fuel gases used for heating, cooking, hot water and vehicles.

Many of the gas appliances sold in Australia are manufactured overseas and call for propane vs LPG. So, you get it home, open the box, and it says that the appliance is made for use with propane vs LPG. Is propane the same as LPG?

But where do you buy Propane in Australia? 

What Size LPG Tank Do I Need and How Many Gas Bottles

The most common size home LPG tank is a 45kg (88 litres) tank installed in pairs. We also supply 90kg and 210kg LPG tanks if you need more gas. Even larger LPG tank sizes are available for heavy users.

A 45kg (88 litres) is the size the majority of people need because they can be either refilled via an LPG tanker or exchanged with another depot filled bottle.

Two gas bottles allow you to use up all of the gas in the first bottle whilst having time to get a refill or an exchange replacement, as you use the second gas bottle.

The primary criteria for selecting the size and quantity of gas bottles installed should be the service considerations and vaporisation rate requirement.

Or, in other words, you never want to run out of gas and you want the gas bottles to supply gas at the rate required by the appliances.

Two LPG Delivery Choices - What Size LPG Tank Do I Need

The size LPG tank you need is should be the standard size 45kg (88 litres) LPG tank for homes, normally have in pairs. A 45kg LPG tank size is needed because this size can be either refilled via an LPG tanker or exchanged for another full LPG tank. Larger size LPG tanks are also available, if needed.

With gas bottle exchange, your empty gas bottles are exchanged for full ones by the delivery driver. 

With automatic tanker delivery, the gas bottles stay in place and an LPG tanker comes to your home to refill your gas bottles in place.

Gas Bottle Exchange Service

With an exchange service, you typically get two 45kg gas bottles. 

The 45kg size is used because they can be moved around by the delivery driver without any special lifting equipment. 

Never Run Out of Gas

The concept is that you call for a delivery when one gas bottle is empty, while you continue with an uninterrupted supply from the other gas bottle. 

You should never run out of gas, as long as you remember to order when the first bottle becomes empty.

Automatic Tanker Refilling

With tanker refill, you may have two 45kg LPG tanks, one or two 90kg LPG tanks or an even larger LPG tank, if you use a lot of gas. The tank size can be as large as required, because it does not have to be moved. 

Another advantage of tanker refill is that the deliveries are often automatically scheduled by the supplier. 

This means you don’t have to check gas bottles or even order gas. It’s all done for you.

There is one limitation with tanker refilling, in that the driver must have a clear line-of-sight between the gas bottles and the tanker.  

If that is not possible, then you will need to go with the exchange service.

Vaporisation Must Match Consumption - LPG Tank Size

The amount of gas that the appliance or appliances are drawing from the gas bottles must be matched by the rate of vaporisation and this affects the size of the LPG tank or vessel you need.

If a gas bottle ices up regularly, it simply means that the vessel is too small for the vaporisation load placed on it. 

Switching to a larger vessel can provide a higher rate of vaporisation.

Heat is absorbed through the vessel shell and into the liquid.

This is known as the “wetted area”.

The larger the tank or the fuller the tank, the more gas that can be vaporised at a given temperature.

Vaporisation tables (as shown below) are used to match the required vaporisation rates to the corresponding vessel size.

Vaporisation tables show the maximum continuous vaporisation rates, in MJ/hr, at different ambient temperatures for each available vessel size.

In instances where a larger vessel is not an option, the only alternative is to supply some artificial means of increasing vaporisation.

The units used are very appropriately call vapourisers.

LPG (Propane) Vaporisation Table

Vaporisation Table Notes:

1. As a simple rule of thumb, when using vessels of say 2.75 or 5.1kL capacities, simply extrapolate between the two nearest size vessels but biasing your calculations on the conservative side. Always consult your supplier’s technical representative for advice.

2. Always check with your supplier’s technical representative that the above vapourisation rates are correct for the particular vessel you have designated.

3. For sites requiring a high vapourisation rate but it is not cost effective to install larger and/or multiple vessels, consider using a vapouriser.

4. Vessels above 3 tonnes or over 7.5kL will be custom designed by supplier to suit customer needs. Figures provided are only rough estimates, based on previous designs.

Final Thoughts

It’s not so much about size, but how you fill them. 

Combined with the number and type of LPG appliances you have, this will help determine the size and number of gas bottles you need for your home.

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The information in this article is derived from various sources and is believed to be correct at the time of publication. However, the information may not be error free and may not be applicable in all circumstances.

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