Tuning of vapor-liquid equilibrium calculations of binary mixtures by using the different experimental data and application of genetic algorithm

Equations of state are the most important means for calculation and estimation of thermodynamic properties in process engineering and extraction and operation of oil and gas industry. Cubic equations of state are very noticeable because of their simplicity in mathematic form of equations and also their good accuracy to predict the thermodynamic properties. As the accuracy of these equations is mostly dependant on the binary interaction parameter, this parameter considered as a base parameter in this research to tuning of the equations. We studied four cubic equations of state, Van der Waals,Redlich- Kwong,Soave-Redlich-Kwong and Peng-Robinson and then we extracted the special mathematic equations of thermodynamic functions such as fugacity coefficient ,volume,enthalpy,entropy and internal energy and K-value related to each equation of states from the general form of these functions .then we programmed the software by visual basic language. This software is able to calculate the optimum value of binary interaction parameter by application of genetic algorithm and available experimental data of vapor-liquid equilibrium entered by user. This method optimizes the calculations and actually increases the accuracy the equations of state very much. Also the values of fugacity coefficient, volume, enthalpy, entropy, internal energy in different thermodynamic states can be calculated by this software. The ability of this software to calculate the thermodynamic function is great and very useful in petroleum engineering and related industry.