Science & Technology in Action

4th Edition

The Natural Gas Network

Bord Gáis Networks

This lesson examines how natural gas is distributed around Ireland. Topics treated include energy value, flow measurement, land reinstatement and safety rules.
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Contains the full lesson along with a supporting toolkit, including teachers’ notes.

Lesson excerpt

Early use of gas
From the early 1800s coal gas was used for street lighting in cities such as London, Paris, Dublin and Cork. Later gas was piped to individual consumers, mainly for lighting. Some large houses had their own gas production facilities. 


New gas-powered devices were developed: heaters, cookers, refrigerators etc. The gas consisted mainly of hydrogen (H2, 50%), methane (CH4, 35%), carbon monoxide (CO, 10%), with small amounts of other gases. It was generally produced by heating coal in the absence of air; the resultant gas was stored in ‘gasometers’. During the mid 1800s other processes were developed to produce combustible gases.
 

Narural Gas
When large deposits of natural gas (up to 99% methane) were found it was considered feasible to pipe it from gas fields (generally off-shore) to major cities. This happened in Britain in the 1960s following the discovery of North Sea gas, and in Ireland in the 1980s following the development of the Kinsale gas field. The changeover entailed:

  • laying high-pressure pipelines over long distances (this was new)
  • replacing nozzles in gas cookers and other equipment with ones of larger diameter; natural gas is mostly methaneand is denser than coal gas
  • conversion of furnaces in power stations, in industry and in private houses
  • replacement of older cast iron gas pipes with newer ones made ofpolyethylene
  • the construction of interconnectors to link different gas supplies.

Because of its carbon monoxide content coal gas was poisonous but natural gas is not inherently poisonous. However large gas leaks in an enclosed space could dilute the oxygen in the air to an unsafe level (from 21% to below 18%).

Quiz questions

  1. Polyethylene is a polymer of methane.
  2. All land traversed by pipelines is returned to its original state following installation.
  3. Liquefaction of gases is used to remove impurities.
  4. The volume of a gas is inversely proportional to its pressure.
  5. Heat of combustion is expressed in moles per joule (mol/J).
  6. Mercaptans are added to natural gas so that it remains in a gaseous form.
  7. Natural gas, which is mostly methane, is denser than coal gas.
  8. ‘Bottled gas’ is a mixture of propane and butane.