Composition
Composition
Natural gas is a gas mixture of various hydrocarbons, of which the largest share (more than 92%) is methane (CH4 ). Other hydrocarbons (ethane, propane, butane and admixtures of heavier hydrocarbons) are present in smaller amounts at a maximum of 6%, and carbon dioxide (CO 2 ) and nitrogen (N 2 ) at a maximum of 3%, and the appearance of helium is also possible. The origin, type and proportion of these impurities in natural gas depend on the type of parent rocks, on the influence of magmatic or hydrothermal processes in the lithosphere, and on natural gas migration processes.
Prescribed quality of natural gas
| Chemical composition | Component | Molar percentage |
| CH4 | metan C1 | minimum 92 |
| C2H6 | etan C2 | maximum 4 |
| C3H8, C4H10, C5H12 | propan C3, butan C4,C4+ | maksimum 2 |
| N2 + CO2 | azot + ugljični dioksid | maskimum 3 |
Combustion of natural gas
For the complete combustion of a unit volume (1m3 ) of natural gas, approximately 2m3 of oxygen is needed. Natural gas burns without smoke, without any soot, does not create ash. During combustion, it releases a large amount of energy, and due to the incomparably lower content of pollutants in the combustion products compared to any other fossil fuel, natural gas is an extremely environmentally friendly energy source.
Basic thermal energetic characteristics
Depending on its quality, the basic thermal energy characteristics of natural gas are within the following limits:
- Wobbe Index W= 44.6 to 54.0 MJ/m3
- Gross Calorific Value of Hg = 30.2 to 47.2 MJ/m3
- Net Calorific Value Hd = 27.2 to 42.5 MJ/m3
- Relative Density d= 0.55 to 0.75 kg/ N m3
- Ignition temperature T= 595 to 640 °C
