°Rankinepseudo-critical temperature of the material 

psipseudo-critical pressure of the material 

DimensionlessGas specific gravity



p_{pc} = 756.8 -131.07 \, \gamma_g - 74 \, \gamma_g^2


T_{pc} = 169.2 +349.5 \, \gamma_g - 3.6 \, \gamma_g^2


Sutton, 1985

H2S = 0%

N2  < 1%

CO2  < 1%

High molecular weight gases, rich in heptanes



p_{pc} = 709.604 - 58.718 \, \gamma_g


T_{pc} = 170.491 +307.344 \, \gamma_g


Guo and Ghalambor (2005)

H2S < 3%

N2 < 5%

Total inorganic compounds < 7% 



p_{pc} = 706 - 51.7 \, \gamma_g - 11.1 \, \gamma_g^2


T_{pc} = 187 +330 \, \gamma_g - 71.5 \, \gamma_g^2


Standing, 1981Total inorganic compounds  = 0%

Low molecular weight California natural gases 


p_{pc} = 787.06 - 147.34 \, \gamma_g - 7.916 \, \gamma_g^2


T_{pc} = 149.18 +358.14 \, \gamma_g - 66.976 \, \gamma_g^2


Elsharkawy et al. (2000)


Retrograde gases and condensates


p_{pc} = 678 - 50\, (\gamma_g - 0.5) - 206.7 \, y_{N_2} + 440 \, y_{CO_2} + 606.7 \, y_{H_2S}


T_{pc} = 326 +315.7 \, (\gamma_g -0.5) - 240 \, y_{N_2} - 83.3 \, y_{CO_2} + 133.3 \, y_{H_2S}


Ahmed (1989)



See also

Natural Science / Physics / Thermodynamics / Thermodynamic system / Pseudo-Critical Point (Tpc, ppc)

[ Fluid Mixture ]

[ Pseudo-Critical Point (Tpc, ppc) ][ Pseudo-Critical Temperature (Tpc) ][ Pseudo-Critical Pressure (Ppc)]

[ Critical Point (Tc, pc) ][ Сritical Temperature Tc ][ Critical Pressure (pc) ]