TY - JOUR
T1 - Modeling of three-phase vapor-liquid-liquid equilibria for a natural-gas system rich in nitrogen with the SRK and PC-SAFT EoS
AU - Justo-García, Daimler N.
AU - García-Sánchez, Fernando
AU - Díaz-Ramírez, Néstor L.
AU - Díaz-Herrera, Enrique
N1 - Funding Information:
This work was supported by the Molecular Engineering Research Program of the Mexican Petroleum Institute under research project D.00484. The authors would like to acknowledge the contribution of the anonymous reviewer, whose constructive criticism led to this improved version of the original manuscript.
PY - 2010/11
Y1 - 2010/11
N2 - In this work, we present the modeling of three-phase vapor-liquid-liquid equilibria for a mixture of natural gas (Hogback gas) containing high concentrations in nitrogen (51.8. mol%) with the SRK and PC-SAFT equations of state. The interest of studying this mixture is due to the experimental evidence of the occurrence of multiple equilibrium liquid phases for this mixture over certain ranges of temperature and pressure. The calculation of the multiphase equilibria was carried out by using an efficient numerical procedure based on the minimization of the system Gibbs energy and thermodynamic stability tests to find the most stable state of the system. The results of the calculated vapor-liquid-liquid equilibria (VLLE) show that the PC-SAFT equation of state predicts satisfactorily the phase behavior that experimentally exhibits this mixture, whereas the SRK equation of state predicts a three-phase region wider than the experimentally observed. The two-phase boundary for this mixture was also calculated through flash calculations, and the results showed that this mixture does not present any gas-liquid critical point.
AB - In this work, we present the modeling of three-phase vapor-liquid-liquid equilibria for a mixture of natural gas (Hogback gas) containing high concentrations in nitrogen (51.8. mol%) with the SRK and PC-SAFT equations of state. The interest of studying this mixture is due to the experimental evidence of the occurrence of multiple equilibrium liquid phases for this mixture over certain ranges of temperature and pressure. The calculation of the multiphase equilibria was carried out by using an efficient numerical procedure based on the minimization of the system Gibbs energy and thermodynamic stability tests to find the most stable state of the system. The results of the calculated vapor-liquid-liquid equilibria (VLLE) show that the PC-SAFT equation of state predicts satisfactorily the phase behavior that experimentally exhibits this mixture, whereas the SRK equation of state predicts a three-phase region wider than the experimentally observed. The two-phase boundary for this mixture was also calculated through flash calculations, and the results showed that this mixture does not present any gas-liquid critical point.
KW - Gibbs energy
KW - Liquefied natural gas
KW - PC-SAFT equation of state
KW - Phase envelope
KW - Stability analysis
KW - Vapor-liquid-liquid equilibria
UR - http://www.scopus.com/inward/record.url?scp=79958783738&partnerID=8YFLogxK
U2 - 10.1016/j.fluid.2010.07.012
DO - 10.1016/j.fluid.2010.07.012
M3 - Artículo
SN - 0378-3812
VL - 298
SP - 92
EP - 96
JO - Fluid Phase Equilibria
JF - Fluid Phase Equilibria
IS - 1
ER -