Selection of State Equation and Innovative Process Design for Removing CO2 by Azeotropic Distillation

Abstract

AbstractA thermodynamic consistency test was performed on the gas‐liquid equilibrium data of three binary mixtures, namely, CH4‐C2H6, CH4‐CO2, and C2H6‐CO2, measured by Wei and Brown at three different temperatures to verify the reliability of the data. Peng‐Robinson (PR), Redlich‐Kwong (RK), and Soave‐Redlich‐Kwong (SRK) equations of state combined with Margles mixing rules were used to fit the gas‐liquid equilibrium data of these three models. The results indicate that the PR‐Margles mixed model can make the average absolute deviation of test data and calculated data pressure and vapor fraction less than 0.19 and 0.0025, respectively, which is superior to RK‐Margles and SRK‐Margles mixed models. Finally, an azeotropic distillation method with C2H6 as entrainer for removing CO2 from natural gas was explored and optimized.