Page 84 - Handbook of Natural Gas Transmission and Processing Principles and Practices

volume, i.e., ), the global molar enthalpy (defined as the global enthalpy of the
2-phase system divided by its global mole number) …

Extensive variables being additive, extensive global variables are obtained by summing the
corresponding total variables of the liquid and gas phases:

(2.4)
As a consequence, the relation between molar phase variables derived from extensive

variables ( , ) and molar global variables

is given as:

(2.5)

The molar proportions of the phases are now introduced through the equation:

(2.6)

By combining Eqs. 2.5 and 2.6, one obtains:

(2.7)
This latter equation that connects global and phase molar properties will be of particular

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