Measurements of enthalpy and phase equilibrium for simulated natural gas mixtures and correlation of the results by a modified Starling equation

• Published in: Cryogenics (Guildford) 1980, Vol.20 (1), p.41-47
• Main Authors: Ashton, G.J., Haselden, G.G.
• Format: Article
• Language: English
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/0011-2275(80)90067-3

New direct measurements of isobaric enthalpy change are reported for a number of 6-component simulated natural gas mixtures containing from 70 to 97% CH 4, 4 to 28% N 2 and higher hydrocarbons to C-4. The pressures explored were in the range of 1.3–5.7 MPa and the temperatures embraced a range starting from about 370K down to a minimum exit temperature of 153K. When phase separation occurred the measured compositions of the co-existing phases are reported. A modified version of the generalised Starling equation was developed in which the parameter γ is made composition dependent since it exerts a major influence on liquid phase behaviour. The resulting interaction parameter was evaluated for 17 binary mixtures of hydrocarbons from methane to n-decane and was expressed as a function of reduced pressure and temperature. Using the appropriate combination rules to go from binary to multicomponent behaviour, this version of the Starling equation was tested against the new experimental data.