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WHAT ARE FOSSIL FUELS?
Fossil fuels are non-renewable resources because they take millions of years to form, and reserves are being depleted much faster than new ones are being formed. The production and use of fossil fuels raise environmental concerns.
The burning of fossil fuels produces around 21.3 billion tonnes (21.3 gigatonnes) of carbon dioxide per year, but it is estimated that natural processes can only absorb about half of that amount, so there is a net increase of 10.65 billion tonnes of atmospheric carbon dioxide per year (one tonne of atmospheric carbon is equivalent to 3.7 tonnes of carbon dioxide). Carbon dioxide is one of the greenhouse gases that enhances radiative forcing and contributes to global warming.
Gaseous forms of Fossil Fuels
Liquefied Petroleum Gas (LPG),
Liquefied Natural Gas (LNG),
Compressed Natural Gas (CNG)
All the three are fossil derived fuels and therefore release, one way or another, sequestered greenhouse gases into the atmosphere.
Liquefied Petroleum Gas (LPG),
Typically the gas is predominantly Propane (C3H8) with some Butane (C4H10) derived mainly from oil refineries We give the chemical formulae because it is the ratio of carbon to hydrogen which is important; the smaller the ratio of C to H, the better for the environment. It follows that methane (CH4) is a better gas in this respect but only if fully burnt!
Liquefied Natural Gas fuel (LNG) is produced from a mixture of raw components but is predominantly methane somewhat better than LPG due to a lesser Carbon to Hydrogen ratio.. The estimate of energy density is 60% compared to diesel. It is still a fossil fuel.
LNG cannot be converted to a liquid by pressure alone but must be cooled to a very low temperature (lower than -160°C), a process which again is energy inefficient, a cost covered up by the oil conglomerates. They need to be in the business!
Compressed Natural Gas (CNG) is, as its name suggests, the close relative of LNG and as a natural gas( Fossil Fuel) it has the same basic characteristics. However, because it is not liquefied it has a lower energy density and is stored at very high pressures; about 200 bar. The estimate of energy density is 25% compared to diesel. |
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