ScienceThe GasDesigners love science and this page is devoted
(initially) to the science of natural gas.
It is proposed to add other science articles and we may start a
dedicated science website if time allows.
Natural gas is a fossil fuel formed from the fossilized
remains of plants and animals. The
process turning the remains from fossil to fuel takes millions of years.
Natural gas consists mostly of methane (CH4) but includes
significant quantities of ethane (C2H6), butane (C4H10),
propane (C3H8), carbon dioxide (CO2), nitrogen
(N2) , helium (He) and hydrogen sulphide (H2S). It is found in oil fields, natural gas
fields, and in coal beds. When methane-rich gases are produced by the anaerobic
decay of non-fossil organic material, these are referred to as biogas. Sources
of biogas include swamps, marshes, and landfills, as well as
sewage sludge and manure by way of anaerobic digesters, in addition to enteric
fermentation particularly in cows. Before natural gas can be used as a fuel, it undergoes
extensive processing to remove almost all materials other than methane. The
by-products of that processing include ethane, propane, butanes, pentanes and
higher molecular weight hydrocarbons, elemental sulphur, and sometimes helium
Once processed, natural gas has no smell so odorants are
added before distribution to end users.
Whilst natural gas is not poisonous, it can kill if it builds up to a sufficient
concentration to displace air to the point where the reduced level of oxygen
will not support life.Being lighter than air, natural gas tends to dissipate into
the atmosphere. However if it is contained, for example within a house,
concentrations can reach explosive mixtures and, if ignited, will result in a
blast that could destroy the building. Methane has a lower explosive limit of
5% in air, and an upper explosive limit of 15%.
The process of burial and fossilization that produces
natural gas, has locked huge amounts of carbon underground (which is good). The burning of natural gas releases this
carbon into the atmosphere thus adding greenhouse gases to the atmosphere (which is not good). The
high usage of natural gas, particularly
in gas fired power stations, releases significant amounts of carbon
atmosphere. Whilst the trend of global warming due to greenhouse
emissions is still under debate, it is clear we need to address this
issue urgently. However it is important to understand that
without the greenhouse gases in our atmosphere, the Earth would
currently be about 30 degrees celcius colder than it is now and as such
life would be very different indeed.
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