Phase equilibria in carbon dioxide expanded solvents: Experiments and molecular simulations

Area of Science:

• Physical Chemistry
• Chemical Engineering

Background:

• Phase equilibria are crucial for designing chemical processes.
• Carbon dioxide expanded liquids (CXLs) offer unique solvent properties.
• Accurate prediction of CXL phase behavior is essential for process optimization.

Purpose of the Study:

• To present molecular simulations and experimental data for phase equilibria of CXLs.
• To evaluate the accuracy of molecular simulations against experimental results.
• To compare molecular simulation predictions with the Peng-Robinson equation of state.

Main Methods:

• Experimental volume expansion measurements using a high-pressure Jerguson view cell.
• Molecular simulations using Gibbs ensemble Monte Carlo (NPT) and canonical ensemble (NVT) methods.
• Simulation of pure components and binary mixtures including various organic solvents and carbon dioxide.

Main Results:

• Experimental and simulation data for phase equilibria of CXLs were obtained.
• Vapor-liquid equilibria predictions for pure components showed good agreement with experimental data.
• Molecular simulations accurately reproduced saturated liquid and vapor densities for all studied systems.
• Simulations provided volume expansion predictions for binary mixtures that were comparable or superior to the Peng-Robinson equation of state.

Conclusions:

• Molecular simulations are a reliable tool for predicting CXL phase equilibria.
• The accuracy of molecular simulations surpasses traditional equations of state in many cases.
• This study highlights the utility of molecular simulation in understanding and designing processes involving CXLs.