LPG

What is LPG gas ?

  • Liquefied Petroleum Gas (LPG) is the generic name for mixtures of hydrocarbons (mainly propane and butane) stored in the liquid state.
  • LPG is colourless, odourless and heavier than air.  A stenching agent is added to give it a distinctive and unpleasant smell, sometimes described as rotten cabbage, so that even a very small leak can be easily detected.
  • LPG burns readily in air and is an excellent fuel for heating, cooking and for automotive use.
  • In most places in the world LPG is propane gas. In other places butane is sometimes used. NZ is unusual in that its LPG is a mixture of both propane and butane. This is why it is important that imported LPG appliances are suitable for NZ’s mixture of gases.

What is natural gas?

  • Natural gas is a highly combustible odourless and colourless hydrocarbon gas largely composed of methane. Natural gas is created in roughly the same manner as oil, by processes that act upon organic matter over millions of years.
  • A stenching agent is added to give it a distinctive and unpleasant smell, sometimes described as rotten cabbage, so that even a very small leak can be easily detected.
  • High combustibility coupled with ease of utilisation and good clean combustion makes natural gas a highly valued resource.
  • Natural gas is primarily used for heating homes, cooking and running appliances such as water heaters and clothes dryers.

 

What is the difference between natural gas and LPG (Liquefied Petroleum Gas)?

Natural gas

  • Consists mainly of methane.  The large proportion of methane is one of the reasons natural gas has such a good safety record.
  • Methane is lighter than air and will disperse relatively easily if there is a gas leak.

Liquefied Petroleum Gas (LPG)

  • Is a hydrocarbon fuel comprised primarily of propane or butane, either separately or as a mixture.
  • LPG is non-toxic, non-corrosive and free of lead.
  • LPG is produced either as a by-product of petroleum, or a by-product in the production of oil and gas, and is stored in tanks and transported by road tanker trucks or in cylinders.
  • LPG is mainly stored in tanks in liquid form and is heavier than air.
  • LPG tends to collect in low points and is more difficult to disperse than natural gas, so is therefore more prone to catch fire or explode if a leak occurs.

 
Uses
LPG has a very wide variety of uses, mainly used for cylinders across many different markets as an efficient fuel container in the agricultural, recreation, hospitality, calefaction, construction, sailing and fishing sectors. It can serve as fuel for cooking, central heating and to water heating and is a particularly cost-effective and efficient way to heat off-grid homes. In the safety font LPG cylinders must be updated to new standards in safety and user experience, giving a huge contribution for domestic usage.

What is LPG made of: LPG Composition

The gases that fall under the “LPG” label, including ethane, ethylene, propane, propylene, normal butane, butylene, isobutane and isobutylene, as well as mixtures of these gases.
The two most common are Propane and Butane.
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.
It is classified as LPG, along with propane, butane and mixes of these gases.

How is LPG Made?  What is the Production Process?

LPG is made during natural gas processing and oil refining.
LPG is separated from unprocessed natural gas using refrigeration.
LPG is extracted from heated crude oil using a distillation tower.
This LPG can be used as is or separated into its three primary parts: propane, butane and isobutane.
It is stored pressurised, as a liquid, in cylinders or tanks.

LPG is Refined from Oil & Natural Gas

LPG is produced during natural gas processing and petroleum refining.
Propane does not occur naturally in isolation.
LPG processing involves separation and collection of the gas from its petroleum base.
LPG is isolated from the hydrocarbon mixtures by separation from natural gas or by the refining of crude oil.
Both processes begin by drilling oil wells.
The gas/oil mixture is piped out of the well and into a gas trap, which separates the stream into crude oil and “wet” gas, which contains LPG and natural gas.
The heavier crude oil sinks to the bottom of the trap and is then pumped into an oil storage tank for refining.
Crude oil undergoes a variety of refining processes, including catalytic cracking, crude distillation, and others.
One of the refined products is LPG.
The “wet” gas, off the top of the gas trap, is processed to separate the gasoline (petrol) from the natural gas and LPG.
Once refined, LPG is stored as a liquid under pressure in gas bottles – cylinders or tanks.
The natural gas, which is mostly methane, is piped to towns and cities for distribution by gas utility companies.
The petrol is shipped to service stations.
The LPG also enters the distribution network, where it eventually finds its way to end users, including Home LPG and Commercial LPG users all around Australia and the world.
At the point of use it once again becomes a gas.