What is LPG

Constiuents of LPG ?

There are two type of gases that can be stored in liquid form with only moderate pressurization — propane and butaneIsobutane, which has the same simple chemical formula as butane but has a different chemical structure, is also used. Usually, butane and isobutane are mixed with propane in various proportions, depending on the intended use of the fuel. Thieir mutual ratio varies from country to country also.


Propane is particularly useful as a portable fuel because its boiling point is -44 F (-42 C). That means that even at very low temperatures, it will vaporize as soon as it is released from its pressurized container. This results in a clean-burning fuel that doesn’t require a lot of equipment to vaporize it and mix it with air. A simple mixer is enough for mixing it with air.
Butane’s boiling point is approximately 31 F (-0.6 C), which means it will not vaporize in very cold temperatures. This is why butane has more limited uses and is mixed with propane instead of being used by itself.
A single gram of propane can generate 47.5 BTU (British Thermal Units) of energy, while butane can produce 46.8 BTU per pound. For comparison, here is how LP Gases stack up to other fuels in terms of energy:

  • Propane :               47.5 BTU per gram
  • Butane :                 46.8 BTU per gram
  • Petrol (Gasoline) : 38.6 BTU per gram
  • Coal :                     22 BTU per gram
  • Wood :                   15.5 BTU per gram

 How LPG is produced

Like oil and natural gas, LP gas is also a fossil fuel. It can be refined from oil and natural gas the same way gasoline is refined from crude oil. Mostly, LPG is produced as byproduct of the refining process of other fuels.

                                                                plantPhoto courtesy Phillips Petroleum Company
Oil refineries produce LP gases in the process of producing other, more commonly used fuels.

When we draw natural gas from the ground, about 90 percent of it is methane. The rest is in the form of various LP gases, which is separated from the methane before the methane is fed into pipelines for use in  homes. The amount of LP gas that comes from natural gas varies, but it is usually from 1 to 3 percent.

LP gases are separated from crude oil, as well. The refining process produces about a 3 percent yield of LP gases, although if refineries were retooled to focus on LP-gas extraction, that number could be as high as 40 percent.

LPG as a Fuel

LP Gas is easy and safe to store, which makes it a very portable fuel. It has been utilized for many different applications, like Small, disposable butane lighters use the LP gas you are most likely to see on a daily basis. They contain a mixture of butane and isobutane.

The common areas of LPG consumption are for cooking, heating and for vehicles. LP gas isn’t only for home and leisure use, however. Many industries use LP gas as a source of heat for metal working, glass working or ceramics. Many industrial forklifts are LP-gas powered because LP gas provides enough power to do heavy lifting while generating reduced fumes and pollutants in confined warehouse spaces.

One of the fastest growing uses of LP Gas is in automobiles. Cars built or converted to run on LP gas are becoming more and more common.

Auto Gas


According to the World Liquefied Petroleum Gas Association (WLPGA), more than 9 million vehicles in 38 countries currently operate on LP gas. It’s not a new idea: Propane-powered vehicles have been around for decades. The benefits include reduced emissions, quoted by WLPGA as “50% less carbon monoxide, 40% less hydrocarbons, 35% less nitrogen oxides (NOx) and 50% less ozone forming potential compared to gasoline”. With government incentives and tax breaks figured in, LP gas used in cars (known as autogas) can be much cheaper than gasoline. Even without the incentives, it is usually much cheaper. Autogas is a high-octane fuel, offering performance comparable to gasoline and diesel, and many owners claim that autogas runs more smoothly, resulting in less wear and tear on engine components.

The easiest way to start using propane for transportation is to buy a vehicle that was designed and built to use autogas. A wide range of manufacturers, including major American car companies like Ford, General Motors and Daimler-Chrysler, offer propane-powered options on some models. Typically, you won’t find these cars on the showroom floor — they have to be special ordered. In an LPG system can be factory installed as an option. Examples of cars that are offered as LP gas models include the Ford Crown Victoria, Dodge Ram, Ford F-150 truck, Chevrolet Cavalier and Toyota Camry.
World wide,most LP gas cars have dual fuel systems — one for petrol and one for LPG. The systems are set to switch automatically between the two fuels as appropriate. This allows owners to use clean, cheap LPG , but they still have the option of a quick fill-up and running on petrol.
However, a large and stable infrastructure of ALDS already exists for vehicles running on LPG.