Modeling VLE Of Co2 In Different Solvents

Abstract

Consumption of fossil fuels is at present a necessity in the industrialized world. Use 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, variety of options are available like adsorption, absorption, membrane separation etc. depending upon the concentration of CO2 in the gas. Most preferred process for the same 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. We have generated VLE data and Henry’s constant for CO2 with different solvents including Ionic Liquids after choosing the proper cohesion factor by the use of programming in MATLAB. We have checked the Absolute Average Deviation (%AAD) for VLE predicted by our programme and experimental data using all models. It is the based for generation of new cohesion factor relationship. The lower value of Henry’s constant indicates the high solubility of CO2 in the solvent. Based on this project work, we concluded that Ionic liquids are a suitable choice for CO2 absorption as higher solubility of CO2 is shown.