Liquefied Petroleum Gas - LPG
What is LPG? Liquefied Petroleum Gas
LPG – Liquefied Petroleum Gas – describes flammable hydrocarbon gases including propane, butane and mixtures of these gases.
LPG, liquefied through pressurisation, comes from natural gas processing and oil refining.
LPG is used as heating, cooking and auto fuel.
In different countries, what is supplied can be propane, butane or propane-butane blends.
Propane is termed as LPG but not all LPG is propane.
Where Does LPG Come From?
LPG comes from drilling oil and gas wells.
It is a fossil fuel that does not occur in isolation.
LPG is found naturally in combination with other hydrocarbons, typically crude oil and natural gas.
LPG is produced during natural gas processing and oil refining.
It is isolated, liquefied through pressurisation and stored in pressure vessels.
Seven LPG Fast Facts
1. LPG (or LP Gas) is the acronym for Liquefied Petroleum Gas or Liquid Petroleum Gas.
2. LPG is a group of flammable hydrocarbon gases that are liquefied through pressurisation and commonly used as fuel.
3. LPG comes from natural gas processing and petroleum refining.
4. There are a number of gases that fall under the “LPG” label, including propane, butane (n-butane) and isobutane (i-butane), as well as mixtures of these gases.
5. LPG gases can all be compressed into liquid at relatively low pressures.
6. LPG is frequently used for fuel in heating, cooking, hot water and vehicles, as well as for refrigerants, aerosol propellants and petrochemical feedstock.
7. LPG is generally stored, as a liquid, in steel vessels ranging from small BBQ gas bottles to larger gas cylinders and LPG storage tanks.
LPG & Natural Gas Liquids – NGLs
The typical LPG gases – propane and butane – are regarded as Natural Gas Liquids - NGLs.
However, not all NGLs are LPG.
Natural gas liquids, also called Condensate, include other hydrocarbons, too.
Interestingly, LNG – liquefied natural gas – is NOT a natural gas liquid.
Raw natural gas, as it comes out of the ground, contains a number of gases and compounds, as well as impurities.
However, it is predominantly methane (CH4) gas, which is more commonly known as natural gas.
The raw natural gas must be processed to obtain pipeline quality clean, dry natural gas (methane), including the removal of impurities.
NGLs – Natural Gas Liquids – or condensate are the heavier hydrocarbons that remain after the methane (natural gas) and impurities are removed.
NGLs include isobutane, ethane, ethene, propene, isobutene, butadiene, pentane, pentene and pentanes plus, as well as propane and butane.
Natural gas liquids (NGL) range from 1% to 10% of the raw natural gas flow.
How is LPG Made?
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 the world.
At the point of use it once again becomes a gas.
What is LPG Used For?
LPG – Liquefied Petroleum Gas – has hundreds, if not thousands, of uses including hot air balloons
The LPG uses most people can name are around the home, in their cars or for their business.
Heating, cooking and hot water are the most common domestic uses.
It is used in leisure time activities including caravans, boats, recreational vehicles and camping.
Business and industry use LPG for a multitude of processes including steam boilers, kilns, ovens and LPG forklifts.
It is also employed as a propellant, refrigerant, vehicle fuel and petrochemical feedstock.
Crop and produce drying, heating greenhouses, hot water for dairies, irrigation pumps and heating animal enclosures are just some of the agricultural applications for LPG.
Transport is also a big user of LPG (Autogas), either as propane or propane mixed with butane, to power various vehicle types.
There are also many, many more LPG applications, including power generation and the hospitality industry.
Benefits of LPG
How Does LPG Liquid Change to Gas? LPG Vaporisation
LPG is stored under pressure, as a liquid, in a gas bottle.
LPG liquid boils and turns back into gas vapour when you release some of the pressure in the gas bottle by turning on your gas appliance.
Liquid LPG changing to gas vapour is called vaporisation.
It takes place as the LPG absorbs heat from the steel walls of the cylinder and the liquid LPG boils.
The steel of the bottle draws heat from the ambient air heat, so cold weather will slow down the rate of vaporisation.
The LPG gas vapour is held in the top of the bottle and the liquid LPG at the bottom, as shown in the accompanying image.
Almost all of the uses for LPG involve the use of the gas vapour, not the liquefied gas.
LPG is Heavier Than Air
In answer to the frequently asked question "Is LPG heavier than air", the answer is "YES".
For example, if the density of air is equal to 1.00, the density of propane is 1.53.
Butane is even heavier, at 2.00. Isobutane is heavier still, at 2.07.
On the other hand, natural gas - methane - is lighter than air, at about 60% of the density of air.
LPG is a versatile, transportable, low carbon fuel.
Using it requires very little infrastructure, which makes it an excellent choice for developing countries, as well as developed countries.
LPG is easy to transport, in cylinders or tankers, making it available virtually everywhere.
Delivery methods can range from very sophisticated to extremely basic.
From requiring considerable capital investment to virtually no investment at all.
Regardless of how it’s delivered, LPG is there when people need it.
Clean, safe and reliable energy for everyone everywhere.