What is the Percentage of Propane and Butane in LPG Gas Mixture – Which Gas is Present in LPG

LPG – Liquefied Petroleum Gas – (Autogas) is primarily comprised of propane, butane, and isobutane in a range of mixtures. It is produced as a co-product of crude oil refining and natural gas processing. The constituents of LPG are gaseous at 20°C and 1 atmosphere pressure (NTP).

LPG – Liquefied petroleum gas or liquid petroleum gas, also denoted as just propane or butane, are both flammable hydrocarbon gases used as fuel for LPG heating gases, cooking and vehicular fuel.

LPG is both propane and butane. As butane does not vaporise (turn from liquid to gas) well at colder temperature, LPG suppliers typically add propane to the percentage of propane and butane in LPG. Propane has a lower boiling point, at -42° vs -0.4°C for butane. So, propane will continue to vaporise in colder climates.

Compared in gaseous volume, butane does have a higher energy content at 111.4MJ/m³ vs propane at 93.2MJ/m³. Natural gas is only 38.7MJ/m³.

Liquefied petroleum gas (LPG or LP gas) is also referred to by its constituent names – propane or butane. LPG are hydrocarbon fuel gases used for heating, cooking, hot water and vehicles.

Most countries have either 100% propane (Australia & USA), an LPG gas mixture of 60:40 propane:butane (NZ & Belgium) or percentage of propane and butane in LPG around 35:65 propane:butane LPG gas mixture (India, Spain & Hungary).

LPG Gas Constituents – What is LPG Made Up Of?

LPG is made up of carbon and hydrogen atoms forming propane and butane whilst natural gas is made up of lighter methane, the simplest carbon and hydrogen molecule.

LPG is comprised primarily of propane and butane, whilst the natural gas primary constituent is methane. LPG is made up of a group of flammable hydrocarbon gases that are liquefied through pressurisation and commonly used as fuel. Natural gas is liquefied cryogenically.

LPG is made up of a number of gases under the LPG products label, including propane, butane, isobutane and mixtures of these gases and are also referred to as natural gas liquids – NGL.

LPG is stored in steel vessels ranging from small BBQ gas bottles to larger gas cylinders and tanks.

Liquefied Petroleum Gas – LPG – constituents are primarily propane, butane, isobutane, butylene, propylene and mixtures of these gases. LPG gas constituents are produced from crude oil reefing and natural gas processing. They are liquid under pressure and gas at room temperature and pressure.

LPG Gas Mixture – Liquefied Petroleum Gas Mixture

A liquefied petroleum gas mixture (LPG gas mixture) consists of flammable hydrocarbon gases that include propane, butane, isobutane and LPG gas mixtures of the three gases. The percentage of propane and butane in an LPG gas mixture ranges from 100% propane to 20% propane and 80% butane.

The chart below shows the LPG gas mixture percentage of propane and butane in LPG for about 17 countries.

Here are some the reported percentage of propane and butane in LPG gas mixtures for other countries.

Note that some countries use a more propane rich LPG gas mixture, in the winter time, to assure proper vaporisation:

Submissions of percentage of propane and butane in LPG corrections and data for addtional countries are most welcome. Just send to [email protected].

LPG – Liquefied Petroleum Gas – is a mixture of flammable hydrocarbon gases used as fuel for cooking, LPG heating gases, hot water and autogas. LPG gas mixture (LPG gas constituents) chemical formula of LPG gas is typically propane (C₃H₈) and butane (C₄H₁₀).

Both LPG gases are frequently sold as the separate LPG gas constituents, being pure propane and pure butane.

LPG gas mixture gases can all be compressed into liquid at relatively low pressures and stored in pressure vessels.

There are a number of gases that fall under the “LPG” category – Liquefied Petroleum Gas…

LPG Heating Gases

LPG heating gases are propane and butane. They are commonly used for generating heat for home heating, hot water, cooking and commercial applications, including boilers. Isobutane is the other common LPG gas but is not typically used for heating. The main uses of isobutane are as a petrol (gasoline) additive, as a refrigerant and as a feed stock for plastics.

LPG Gas Mixture – Gases Present in LPG – Components of LPG

LPG is not just a single gas and can be an LPG gas mixture. LPG describes a category of flammable hydrocarbon gases. LPG gases (primarily propane and butane) can all be compressed into liquid at fairly low pressures.

Typically, LPG is either 100% propane, 60% propane and 40% butane, or 35% propane and 65% butane, depending on the country and region.

Other gases that are also potential LPG gas mixture constituents include ethane, ethylene, propylene, butylene and isobutylene. An LPG gas mixture of these constituents gases, is also referred to as natural gas liquids – NGL.

LPG gas mixture constituents include propane, butane (n-butane) and isobutane (i-butane), as well as LPG gas mixtures of these gases.

Other gases that are also LPG gas constituents include ethane, ethylene, propylene, butylene and isobutylene, so an LPG gas mixture of these constituents gases, is also referred to as natural gas liquids – NGL.

What is the Percentage of Propane and Butane in LPG Gas Mixture

What the percentage of propane and butane in LPG gas mixture varies by country and sometimes by where you are within a country. LPG gas mixture percentage of propane and butane in LPG may depend on both location and season.

The percentage of propane and butane in LPG gas mixture can vary by season, with a higher percentage of propane vs butane in LPG during the winter months, depending on the location.

For example, in the US and Australia, LPG gas mixture is not a mixture at all, it is just propane regardless of season.

The exception to this is autogas LPG in Australia, where the percentage of propane and butane in LPG gas mixture varies up to 100% propane.

In New Zealand, LPG gas mixture percentage of propane and butane in LPG gas mixture is 60% propane and 40% butane, which is typical for NZ.

However, sometimes the percentage of propane and butane in LPG are different for the North Island vs the South Island during winter.

The percentage of propane and butane in LPG gas mixture is usually determined based on what is available on the supply side.

Percentage of Propane & Butane in LPG Gas Mixture Depends on the Season

In some areas or countries, percentage of propane and butane in LPG gas mixture is changed depending on the season.

Propane’s biggest advantage is a lower boiling temperature, at -42° vs -0.4°C for butane.

So, propane will continue to vaporise – turn to gas – even in colder climates.

This is why the the percentage ratio of propane and butane in LPG gas mixtures may be increased during the winter season.

LPG Terminology Varies by Country as does Percentage of Propane and Butane in LPG

So, any of these gases or LPG gas mixtures of these gases can be legitimately referred to as LPG gas constituents. However, in a given country, the term LPG is generally understood to be whatever the typical percentage of propane and butane in LPG are for that country.

For example, in Australia, we call it LPG but it is propane. So, no LPG gas mixture for regular LPG.

Autogas in Australia can be either pure propane or an LPG gas mixture of propane and butane.

In NZ, LPG gas mixture is propane and butane with the percentage of propane and butane in LPG changinh by season.

Alternatively, the term “LPG” may not be used at all, with the gas being referred to by the specific gas name.

This is the case in the USA, where LPG is just called “propane”. So, again, no LPG gas mixture.

In the UK, consumers have choices.  The fuel type LPG is referred to as either propane, butane or LPG, depending on what gas is present in the customer’s choice.

In other countries, they call it “GPL” or “GLP” instead of “LPG”, as the acronym is based on different languages and syntax.

For example, in French it is “gaz de pétrole liquéfié” or in Spanish it is “gas licuado de petróleo”.

Other Names for LPG

What does LPG stand for?   LPG is an acronym for either Liquefied Petroleum Gas or Liquid Petroleum Gas. LPG goes by many other names and the percentage of propane and butane in LPG can sometimes be confusing.

It is also called LPG Gas, LP Gas, Propane, BBQ Gas, Camping Gas or Autogas, as well as all of the other specific gas names.

LPG as Propane

Propane is a flammable hydrocarbon gas liquefied through pressurisation.

There are 3 carbon and 8 hydrogen atoms in a propane molecule. 

The chemical formula of LPG gas – chemical formula for propane is C₃H₈.  (Propane molecule model shown)

Propane is not made or manufactured, it is found naturally in combination with other hydrocarbons.

Propane is produced during natural gas processing and petroleum refining.

Propane processing involves the separation and collection of the gas from its petroleum base and other Natural Gas Liquids (NGLs).

Following its refinement, LPG is stored and distributed as a liquid under pressure until used, at which point it is utilised as either a liquid or a gas (vapour).

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

Large users may utilise bigger LPG storage tanks.

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

It is commonly used for heating and cooking.

Propane is frequently used in Autogas, alone or in a propane-butane mix.

LPG as Butane

Butane (n-butane) is also considered to be LPG.

Butane is a flammable hydrocarbon gas that is liquefied through pressurisation. 

The chemical formula of LPG gas as butane is C₄H₁₀, with 4 carbon and 10 hydrogen atoms in a butane molecule. (Butane molecule model shown)

Butane comes from natural gas processing and oil refining.

Propane processing involves the separation and collection of the gas from its petroleum base and other Natural Gas Liquids (NGLs).

Following its refinement, LPG is stored and distributed as a liquid under pressure until used, at which point it is utilised as either a liquid or a gas (vapour).

It is used for heating and cooking, as well as auto fuel.

Butane is frequently used in Autogas in a propane-butane mix.

Butane is also used as a propellant and refrigerant, as well as a petrochemical feedstock.

Butane is supplied to businesses that require Butane, as opposed to propane.

Butane has some specific applications where it has advantages over propane.

LPG as Isobutane

Isobutane (i-butane) is an isomer of butane, with the same chemical formula as butane but different physical properties.

Isobutane is converted from butane in a process called isomerization. 

So, it has the same chemical formula of LPG gas as butane —  C₄H₁₀  — but has a different arrangement of its atoms, as you can see in the 3-D model images. (Isobutane molecule model shown)

As with normal butane, isobutane is a flammable hydrocarbon gas that is liquefied through pressurisation.

It also has different physical properties from normal butane (n-butane).

In addition to being used as a fuel, isobutane is commonly used as a refrigerant and a propellant.

Isobutane has very low global warming potential and insignificant ozone depletion potential.

However, its main use is in refineries to increase octane of gasoline and make it cleaner burning.

LPG Properties Vary by the Percentage of Propane and Butane in LPG Gas Mixture

As discussed, not all LPG gases are the same because the percentage of propane and butane in an LPG gas mixture vary.

The LPG gas constituents have different physical properties and formulae.

LPG physical properties include specific gravity (density), boiling point, pressure, vapour expansion, energy content, combustion facts, flame temperature, flash point & more.

This chart shows some of the physical properties of the three most common LPG gas constituents – propane, butane and isobutane. An LPG gas mixture of any of these 3 gases would result in a different set of LPG properties…

  Note: Some numbers have been rounded.