Dependence of mine gas calorific value on methane concentration
| Methane concentration in mine gas (%) | 30 | 40 | 50 | 0 | 70 | 80 | 90 |
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Calorific value (MJ/kg) | 10.5 | 14.3 | 17.8 | 21.3 | 24.7 | 28.5 | 32.1 |
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In most cases, methane concentration in mine gas ranges within 35–40% vol. For use as a fuel, gas shall have the lower calorific value of at least 16.0 MJ/m³ which corresponds to the CH4 content of 46% vol.
A similar situation (impossibility of direct gas use as a fuel due to its extremely low calorific value) exists with regard to associated petroleum gas (APG) showing high nitrogen content (in some cases up to 90% vol.).
Grasys membrane plants allow treating mine gas as well as associated petroleum gas with high nitrogen content for further use as a fuel at gas-fired reciprocating plants and gas turbine power plants, boiler houses.
