LPG: The Alternative Fuel of Choice

Liquefied Petroleum Gas, commonly known as LPG, iscauses ignition and suffocation hazards if not properly
generally used as a fuel in heating appliances, indealt with - and hence the odourant.
vehicles, as well as a refrigerant and an aerosolSo why use LPG at all? LPG is the lowest carbon
propellant. It has rapidly replaced CFC's oremitting fuel available. It is not dangerous to the
Chlorofluorocarbons to reduce the damage to thehealth of the users, as it burns cleanly leaving no soot
ozone layer. LPG is essentially a mixture of Butaneand minute quantities of sulphur emissions. It does
and Propane, and the most commonly marketed rationot pose any water or ground pollution hazards
is 40:60. This ratio varies from season to season, aseither. This, plus the fact that huge quantities of LPG
in winter more Propane is used and in summer morecould be stored in bulk tanks and stored underground
Butane is used. A powerful odourant called Ethanethiolor underwater if required, tends to make it the
is added in minor amounts to LPG to help in easynumber one cooking fuel in some countries. It is also
detection of any leakage.referred to as auto gas when it is used in
LPG is primarily derived from fossil fuels. Theautomobiles, or to fuel internal combustion engines. It
maximum amount of LPG is extracted during theis also used as an alternative fuel for sparking ignition
refinement of crude oil and the next most commonengines. It is non corrosive, non toxic and does not
source is oil and gas streams, as and when theycontain any lead additives. It also has a very high
emerge from the earth. LPG evaporates at normaloctane rating (108 RON). It has a specific calorific
room temperature and pressure. To prevent this,value of 46.1 MJ/kg, which is better than both petrol
LPG is supplied in pressurised cylinders and steeland diesel.
bottles. These bottles are never filled completely soLPG constituents Propane and Isobutane, at high
as to accommodate thermal expansion. Normally,purity, are used to make hydrocarbon refrigerants.
they are filled to 80- 85 % of their capacity. TheThis is done because hydrocarbons tend to be more
ratio of the liquefied gas to vaporised gas also variesefficient and are generally cheaper as they are
depending upon the pressure, temperature andbyproducts of fuel production. Millions of households
composition. It is typically around 1:250.worldwide use LPG as cooking fuel, and in some
Vapour pressure for a substance is the pressure atcountries like Brazil the government also gives special
which it becomes liquid and it varies depending upondiscounts on LPG prices to people below the poverty
composition, pressure and temperature. LPG isline. LPG is definitely worth a try, especially when the
heavier than air and if leaked tends to flow along theentire world seems to be concerned about carbon
floor and settles in low spots like basements. Thisfootprints and green living.