Propane

Propane is a three-carbon alkane, normally a gas, but compressible to a transportable liquid. It is derived from other petroleum products during oil or natural gas processing. It is commonly used as a fuel forengines, oxy-gas torches, barbecues, portable stoves and residential central heating.When used as vehicle fuel, it is commonly known as liquefied petroleum gas (LPG or LP-gas), which can be a mixture of propane along with small amounts of propylene, butane, and butylene. An odorant such asethanethiol or thiophene is added so that people can easily smell the gas in case of a leak.Contents [hide]1 Etymology2 Properties and reactions2.1 Energy content[/list]3 Uses3.1 Domestic and industrial fuel3.2 Refrigeration3.2.1 In motor vehicles[/list]3.3 Vehicle fuel3.4 Other[/list]4 Propane risks and alternate gas fuels5 Propane Tank Remainder Measurement6 Sources7 History8 Retail cost8.1 United States[/list]9 See also10 References11 External links[/list][edit]EtymologyIts name was made from the "prop" prefix (denoting 3 carbon atoms in the hydrocarbon chain) and the "-ane" suffix (single c-c bonds only).[edit]Properties and reactionsPropane undergoes combustion reactions in a similar fashion to other alkanes. In the presence of excess oxygen, propane burns to form water and carbon dioxide.C3H8 + 5 O2 → 3 CO2 + 4 H2O + heatPropane + Oxygen → Carbon Dioxide + WaterWhen not enough oxygen is present for complete combustion, incomplete combustion occurs when propane burns and forms water, carbon monoxide, carbon dioxide, and carbon.C3H8 + 3.5 O2 → CO2 + CO + C + 4 H2O + heatPropane + Oxygen → Carbon Dioxide + Carbon Monoxide + Carbon + WaterUnlike natural gas, propane is heavier than air (1.5 times as dense). In its raw state, propane sinks and pools at the floor. Liquid propane will flash to a vapor at atmospheric pressure and appears white due to moisture condensing from the air.When properly combusted, propane produces about 50 MJ/kg. The gross heat of combustion of one normal cubic meter of propane is around 91 megajoules[1]Propane is nontoxic; however, when abused as an inhalant it poses a mild asphyxiation risk through oxygen deprivation. Commercial products contain hydrocarbons beyond propane, which may increase risk. Commonly stored under pressure at room temperature, propane and its mixtures expand and cool when released and may cause mild frostbite.Propane combustion is much cleaner than gasoline combustion, though not as clean as natural gas combustion. The presence of C–C bonds, plus the multiple bonds of propylene and butylene, create organic exhausts besides carbon dioxide and water vapor during typical combustion. These bonds also cause propane to burn with a visible flame.Greenhouse gas emissions factors for propane are 62.7 kg CO2/ mBTU[2] or 1.55 kg of CO2 per litre[3] or 73.7 kg / GJ[4].[edit]Energy contentThe energy density of propane is 46.44 megajoules per kilogram[5] (91,690 BTU per gallon).
 
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