The Study of Gas Mixture Non-Ideality

Abstract

In the realm of chemical thermodynamics, the investigation primarily centers on the dynamics of pure substances, sidelining the molecular interplay forces that are pivotal among disparate molecular entities in a mixture. This approach is instrumental in elucidating the principles governing the non-ideal behavior of gases. The divergence from ideal gas behavior in both singular gases and their mixtures is quantifiable by the disparity between their actual conduct and the theoretical predictions founded on ideal gas laws. This study endeavors to evaluate the thermodynamic characteristics of a CH4-CO2 mixture through the application of the Van Der Waals and Soave-Redlich-Kwong cubic state equations, utilizing a computational program designed as a thermodynamic computational tool. The outcomes of this study facilitate the characterization of non-ideal gas mixture behaviors, discerning the compressibility factor's variation in response to pressure alterations across diverse temperatures and compositions within a specified pressure ambit. Concurrently, the availability of empirical data in scientific literature enables the corroboration of the more precise state equation, which can be subsequently employed for examining the authentic behavior of gas mixtures. Additionally, the multitude of thermodynamic models delineated in scholarly articles permits the computation of associated thermodynamic energies for each case study, along with the determination of activity and fugacity coefficients, which are integral in phase equilibrium analyses of gas mixtures. The findings underscore the dominance of attractive forces at diminished pressures and repulsive forces at escalated pressures. The analytical comparison with empirical data demonstrates that the Soave-Redlich-Kwong equation, especially when considering the acentric factor—a parameter that accounts for the molecular dimensions in the mixture—exhibits superior precision in depicting the real behavior of the gas mixtures.