Prediction of homogeneous azeotropes by Wilson equation for binary HFCs and HCs refrigerant mixtures

A simple approach based on Newton's method using Wilson activity coefficients equation and Antoine equation is proposed to determine the binary homogeneous azeotropes for hydrofluorocarbons (HFCs) and hydrocarbons (HCs) mixtures. With the known Wilson parameters at a certain temperature, the azeotropic composition at this temperature range can be evaluated. Only one point of the measured VLE data is required to evaluate the Wilson parameters firstly if they are unavailable. The method is verified with six binary systems, which are ethane (HC-170) + trifluoromethane (HFC-23), difluoromethane (HFC-32) + propane (HC-290), pentafluoroethane (HFC-125) + propane (HC-290), 1,1,1,2-tetrafluoroethane (HFC-134a) + n-butane (HC-600), 1,1,1-trifluoroethane (HFC-143a) + n-butane (HC-600) and propane (R290) + 1,1,1,2,3,3,3-heptafluoropropane (R227ea) mixtures. Good agreements are found between the calculated results and reference data.