The Comparative Study of Cohesion Factors for the Prediction of VLE of CO2-Solvent System

Abstract

Consumption of fossil fuels leads to Carbon Dioxide (CO2) being formed and CO2 is the greenhouse gas responsible for most of the anthropogenic global warming. Even the fuel used for the industrial uses contains CO2. For capturing pre combustion CO2, Most preferred process is physical absorption as it is energy efficient. The solvent selection in physical absorption is depend on the solubility of CO2 in solvent and VLE. For VLE prediction from Equation of state, the choice of cohesion factor is important task. We have used five cohesion factor proposed by different authors. Cohesion factor relationship can be chosen based on the representation of vapor pressure data and hence the vapor pressure data of all the solvents and CO2 is generated using equation of state. Almost 2500 data points are generated using equi-fugacity criteria programmed in MATLAB for the vapor pressure estimation using Peng Robinson Equation of State. These vapor pressure data are compared with pseudo experimental and experimental data available in the literature. Based on the predicting capacity of cohesion factor three models were chosen to predict the VLE of some binary system. Using these models we have generated VLE data for four solvents with CO2 by the use of programming in MATLAB. It was found that Methanol is best among the solvent studies in the present work. However, it was also found that the cohesion factor used to predict the VLE data can be further improved by using component specific paramet.