Computational Screening of Physical Solvents for CO₂ Pre-combustion Capture

Area of Science:

• Computational chemistry and materials science.
• Focus on chemical engineering solutions for carbon capture.
• Application of molecular modeling in chemical process development.

Background:

• Pre-combustion capture of carbon dioxide (CO2) is essential for reducing greenhouse gas emissions.
• Physical solvents offer a promising alternative to chemical absorption methods.
• Identifying effective physical solvents requires understanding gas-solvent interactions and physical properties.

Purpose of the Study:

• To computationally screen physical solvents for efficient CO2 pre-combustion capture.
• To identify novel solvents with high CO2 solubility and CO2/H2 selectivity.
• To elucidate the relationships between solvent properties and gas absorption performance.

Main Methods:

• Integration of commercial and in-house computational databases (NIST, NETL).
• Application of chem-informatics and molecular modeling techniques.
• Systematic study of gas solubilities (CO2, H2, N2, H2O) and solvent fractional free volume (FFV).

Main Results:

• Diethyl sebacate identified as a promising hydrophobic solvent with favorable physical properties and absorption performance.
• Diethyl sebacate demonstrated high CO2 solubility and CO2/H2 selectivity due to favorable CO2 interactions and intermediate FFV.
• Established correlations between functional group interactions, FFV, and gas solubilities; CO2 interactions are stronger than N2 and H2 but weaker than H2O.

Conclusions:

• Diethyl sebacate is a viable candidate for CO2 pre-combustion capture, confirmed by experimental validation.
• Optimal physical solvents for CO2 capture should possess functional groups that strongly interact with CO2 while minimizing FFV.
• Understanding gas-solvent interactions and FFV is key to designing high-performance physical solvents for carbon capture.