GasDesign

Science

The 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 and nitrogen.

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 into the 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.