View source for Liquefied petroleum gas

[[Category:Done 2018-07-20]] 
[[File:509px-Cylinder,gas,HP,_Tamil_Nadu451.jpeg|400px|framed|right|Figure 1. An LPG cylinder.
<ref>Wikimedia Commons. (May 29, 2015). ''Cylinder Gas'' [Online]. Available: http://commons.wikimedia.org/wiki/File:Cylinder,gas,HP,_Tamil_Nadu451.jpeg#/media/File:Cylinder,gas,HP,_Tamil_Nadu451.jpeg</ref>]]

<onlyinclude>'''Liquefied petroleum gas''' or '''LPG''' is a type of [[hydrocarbon]] [[gas]] that is obtained by refining [[crude oil]] or processing [[natural gas]]. This gas is composed of either [[propane]] and [[butane]] by themselves or as a mixture of the two.</onlyinclude><ref name="EIA">US EIA. (June 2, 2015). ''Liquefied Petroleum Gases - Index'' [Online]. Available: http://www.eia.gov/tools/glossary/index.cfm?id=L</ref> In addition to its use as a fuel for cooking and heating, LPG is also important for use in manufacturing applications, as a fuel for cars, and it can be used to power [[cogeneration]] plants.<ref name="RE2">Origin Energy. (June 2, 2015). ''What is LPG?'' [Online]. Available: http://www.originenergy.com.au/blog/about-energy/what-is-lpg.html</ref>

==Production==
Liquefied [[petroleum]] gas is produced during the refining process of crude oil or extracted during the processing of natural gas. The gases produced in this process are mainly propane and butane with small amounts of other gases. These gases are liquefied through pressurization to make them easier to transport and store.<ref name="EIA"/>

To liquefy the fuel, gases are stored in sturdy tanks and held at high [[pressure]]s—about 20 times [[atmospheric pressure]]. These tanks have additional safety features because of this extreme pressurization, mainly a built-in shutoff valve to seal the tank if there are leaks and an extra-sturdy design.<ref name="RE1">AltFuels. (June 2, 2015). ''Liquefied Petroleum Gas'' [Online]. Available: http://www.altfuels.org/backgrnd/altftype/lpg.shtml</ref> Since LPG generally has no odour, small amounts of ethanethiol (a foul smelling [[mercaptan]], a type of [[odorant]]) are added to help people smell dangerous gas leaks.

==Use==
LPG has a high [[caloric value]], meaning that it is a good [[energy]] source as it provides a high level of [[heat]]. It is also a valuable [[fuel]] as it has almost no [[sulfur]] content, which results in cleaner [[combustion|burning]].<ref name="RE3"/> About half of the LPG used is consumed for heating and cooking and essentially is used in place of natural gas. The remaining 50% of LPG is split more or less equally between use in cars and industrial uses. Overall, LPG provides less than 2% of the total energy people use but it is still a major alternative to gasoline.<ref name="RE3">Chris Woodford. (June 2, 2015). ''LPG'' [Online]. Available: http://www.explainthatstuff.com/lpg.html</ref>

When used, LPG is generally delivered by trucks in a large tank and placed outside a home or other building. In addition, reusable gas canisters are available for powering stoves, [[heater]]s, and barbecues. Small canisters of LPG are also available for portable hair styling tools.<ref name="RE3"/>

Two major disadvantages of the use of LPG are safety and cost. The high pressure needed to store LPG results in occasional tank bursts if canisters are not stored properly and maintained. In addition, LPG is highly [[flammable]]. However, suppliers take many safety precautions to ensure that LPG is as safe as ordinary natural gas supply. The cost of LPG is several times higher than ordinary natural gas, but LPG might prove to be a good option if access to natural gas is not available.<ref name="RE3"/>

==Use as a Vehicle Fuel==
[[File:640px-In-vehicle_LPG_bottle2.jpg|400px|framed|right|Figure 2. A vehicle's LPG tank.<ref>Wikimedia Commons. (June 8, 2015). ''In-vehicle LPG bottle'' [Online]. Available: http://commons.wikimedia.org/wiki/File:In-vehicle_LPG_bottle_001.JPG#/media/File:In-vehicle_LPG_bottle_001.JPG</ref>]]
Liquefied petroleum gas can be used as an alternative fuel to power [[internal combustion engine]]s as it is more cleanly burning than [[gasoline]] and can produce lower amounts of some harmful emissions such as [[carbon dioxide]].<ref name="RE4">US Department of Energy. (June 2, 2015). ''Propane, Liquefied Petroleum Gas'' [Online]. Available: https://www.fueleconomy.gov/feg/lpg.shtml</ref> An estimated 6 million European vehicles run on LPG and there are around 17,500 [[gasoline station]]s in Europe supplying this fuel.<ref name="RE3"/>

One of the major benefits of using LPG as an alternative fuel is that it is usually less expensive than gasoline.<ref name="RE1"/> Additionally, the careful design and safety features of the tanks make them slightly safer to use than gasoline simply because they have a shut-off valve. This minimizes the risk of an LPG fire if used as a vehicle fuel.<ref name="RE1"/>  LPG can also be used as a fuel without taking away from vehicle performance.<ref name="RE4"/> The use of LPG also helps with the issue of importing fuels for use from other countries as 90% of LPG used in the US comes from domestic sources.<ref name="RE4"/>

However, the availability of vehicles that are LPG-fueled is limited. Some existing vehicles can be converted to use this LPG with installations, but involves installing a separate fuel system as the liquid is stored in highly pressurized fuel tanks.<ref name="RE4"/> In addition, it is harder to find places to refill LPG as it is not as widely used as gasoline or [[diesel]], and fewer miles can be traveled on a single tank of LPG.<ref name="RE4"/>

==For Further Reading==
*[[Fossil fuel]]s
*[[Fossil fuel formation]]
*[[Fossil fuel extraction]]
*[[Heat engine]]
*Or explore a [[Special:Random| random page]]

==References==
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