Calculation of vapor-liquid-liquid equilibrium with cubic equations of state and a corresponding states principle

1984 ◽  
Vol 23 (3) ◽  
pp. 348-354 ◽  
Author(s):  
David S. H. Wong ◽  
Stanley I. Sandler
Keyword(s):  
Equations Of State ◽  
Corresponding States ◽  
Liquid Equilibrium ◽  
Corresponding States Principle ◽  
Vapor Liquid

VAPOR–LIQUID EQUILIBRIUM MODELING FOR MIXTURES OF HFC-32 + ISOBUTANE AND HFC-32 + HFO-1234ze(E)

2011 ◽  
Vol 19 (02) ◽  
pp. 93-97 ◽  
Author(s):  
RYO AKASAKA
Keyword(s):  
Free Energy ◽  
Helmholtz Free Energy ◽  
Equations Of State ◽  
Dew Point ◽  
Working Fluid ◽  
Liquid Equilibrium ◽  
Vapor Liquid Equilibrium ◽  
Equilibrium Modeling ◽  
Independent Variables ◽  
Vapor Liquid

Vapor–liquid equilibrium (VLE) have been successfully modeled for the binary mixtures of difluoromethane (HFC-32) + isobutane and difluoromethane + trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)). These mixtures are considered as possible replacements for conventional refrigerants far from negligible global warming potential (GWP). A multifluid approach explicit in the Helmholtz free energy forms the basis of the model. The independent variables are the temperature, density, and composition. Accurate published equations of state for pure HFC-32, isobutane, and HFO-1234ze(E) are incorporated to calculate the Helmholtz free energy of each component. Typical uncertainties of bubble- and dew-point pressures calculated using the model are within 2%. Although adjustable parameters of the model are determined only from experimental VLE data, it is highly probable that the model reasonably predicts other thermodynamic properties such as enthalpy and heat capacities. Therefore, the model allows practical design and simulation of refrigeration systems using the mixtures as a working fluid.

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