Symbol | Description | Units |
---|---|---|

M | Molar mass of the mixture | kg/kmol |

X_{j} |
Mole fraction of component j | - |

M_{j} |
Molar mass of component j | kg/kmol |

Symbol | Description | Units |
---|---|---|

z_{s} |
Standard compression factor | - |

X_{j} |
Mole fraction of component j | - |

b_{j} |
Summation factor for component j | - |

The summation factor for each component (b

Symbol | Description | Units |
---|---|---|

ρ_{r} |
Relative density | - |

X_{j} |
Mole fraction of component j | - |

M_{j} |
Molar mass of component j | kg/kmol |

Z_{s} |
Standard compression factor | - |

Constant | Description | Value | Units |
---|---|---|---|

z_{air} |
Compression factor of dry air (1995) | 0.99958 | - |

M_{air} |
Molar mass of dry air (1995) | 28.9626 | kg/kmol |

z_{air} |
Compression factor of dry air (2016) | 0.999595 | - |

M_{air} |
Molar mass of dry air (2016) | 28.96546 | kg/kmol |

The molar mass of dry air (M

Symbol | Description | Units |
---|---|---|

CV_{c} |
Calorific value on molar basis | KJ/mol |

x_{j} |
Mole fraction of component j | - |

CV_{j} |
Calorific value of component j | KJ/mol |

The component calorific value (CV

The Superior calorific value is calculated as per 1995 using ISO 6976 - 2016 - Table 3, Gross calorific values on a molar basis for components of natural gas in the ideal gas state at various combustion reference temperatures

The Inferior calorific value is calculated as follows

Symbol | Description | Units |
---|---|---|

CV_{c} |
Calorific value on molar basis | KJ/mol |

x_{j} |
Mole fraction of component j | - |

b_{j} |
Number of hydrogen atoms present in each molecule of component j | - |

L | Enthalpy of vaporization of water | - |

Symbol | Description | Units |
---|---|---|

CV_{m} |
Calorific value based on mass | MJ/kg |

CV_{c} |
Calorific value on molar basis | KJ/mol |

M | Molar mass of the mixture | kg/kmol |

Symbol | Description | Units |
---|---|---|

CV_{m} |
Calorific value based on mass | MJ/kg |

x_{j} |
Mole fraction of component j | - |

M_{j} |
Molar mass of component j | kg/kmol |

M | Molar mass of the mixture | kg/kmol |

CV_{j} |
Calorific value of component j | MJ/kg |

The component calorific value (CV

Symbol | Description | Units |
---|---|---|

CV_{v} |
Calorific value based on volume | MJ/Sm^{3} |

CV_{c} |
Calorific value on molar basis | KJ/mol |

p_{b} |
Base pressure | bar a |

t_{b} |
Base temperature | K |

Constant | Description | Value | Units |
---|---|---|---|

R | Universal Gas Constant | 8.314459848484848 | J/mol/K |

Symbol | Description | Units |
---|---|---|

CV_{v} |
Calorific value based on volume | MJ/Sm^{3} |

x_{j} |
Mole fraction of component j | - |

CV_{j} |
Calorific value of component j | MJ/Sm^{3} |

Z_{s} |
Standard compression factor | - |

The component calorific value (CV

- ISO 6976, Natural gas – Calculation of calorific values, density, relative density and Wobbe Index from composition, using table data from 1995 or 2016