What is natural gas? Characteristics

What is natural gas? Energy for comfort

These days, natural gas is an energy source which runs underground in most cities in the developed world, providing maximum comfort to homes and the energy needed by industry.

Composition and properties

Natural gas is a hydrocarbon consisting mainly of methane, although it usually also contains a variable proportion of nitrogen, ethane, CO₂, H₂O, butane, propane, mercaptans and traces of heavier hydrocarbons. Methane is one carbon atom joined to four hydrogen atoms (CH₄) and can constitute up to 97% of natural gas.

CH₄

Molecular formula

18.2

Molecular weight of mixture

-160.0 °C

Boiling point at 1 atmosphere

-180.0 °C

Melting point

0.61

Vapour density (Air =1) at 15.5

0.554

Liquid density (Water=1) at 0°/4 °C

1 litre of liquid becomes 600 litres of gas

Expansion ratio

Slightly soluble from 0.1 to 1.0%.

Water solubility at 20 °C

Clean energy

Natural gas is a clean energy, the least polluting of all conventional energies. It does not harm the environment or damage the landscape where its pipes are laid, as these are channelled underground.

Characteristics of natural gas

Natural gas is consumed in the state in which it is found in nature. From extraction at the deposit to its arrival at homes and points of consumption, natural gas does not undergo any transformation process.
The simpler molecular structure of natural gas enables a clean burn, so its combustion does not produce solid particles or sulphur.
Natural gas is one of the cleanest fossil energy sources as it emits the least polluting gases (SO₂, CO₂, NOx and CH₄) per unit of energy produced.

Carbon emissions (g CO₂/usable kWh generated)

*CO₂ emissions associated with electricity consumption according to 2010 electricity mix data from IDAEA Source: Gas Natural Foundation – Technical energy and environmental guides.18. The contribution of natural gas to emissions reduction in Spain. (2009)

Emission factor (g/usable kWh generated)

Source: Gas Natural Foundation – Technical energy and environmental guides.18. The contribution of natural gas to emissions reduction in Spain. (2009)

In its natural state, natural gas is odourless, colourless and tasteless but in order to warn of its presence in the event of leaks, an aroma compound (mercaptans) is added, giving it its characteristic smell of rotten eggs.

It needs ignition for combustion
Its relative density makes it lighter than air, so that leaks or emissions quickly dissipate into the upper layers of the atmosphere, making it less likely to form explosive mixtures in the air.
It is efficient and plentiful.
Non-corrosive.