1Chemical Engineering Department, Institute of Technology, Nirma University, Tragad Patia, Ahmedabad, Gujarat −382481, India, E-mail: milind.joshipura@nirmauni.ac.in.
2Chemical Engineering Department, the M S University of Baroda, Vadodara, Gujarat India. 390001, E-mail: sudhir_dabke@yahoo.co.in.
Major factor in the success of predictive capability of cubic equations of state (CEOS) is its temperature dependency through cohesion factor. Six cohesion function models for Peng Robinson (PR) Equations of State (EOS), available in literature have been compared. Comparison is based on estimation of pure component vapor pressures. Three hundred and thirteen compounds making out twenty nine families have been considered in the study. Vapor pressures have been predicted using equi-fugacity criteria based algorithm implemented in MATLAB. New correlations for cohesion factor are proposed using very simple methodology. The proposed models were found valid for some specific families of the chemical compounds as well as for specific range of temperature. No single model was found suitable to represent all the families.
Alpha/Cohesion Function, Equation of State, Peng Robinson, EOS, Vapor Pressure
