(711d) Development of a Group Contribution Methodology for Multi-Functional Amines in the Context of Carbon Capture Applications

Physical property models are developed within the framework of the statistical associating fluid theory (SAFT) to describe and predict the vapor-liquid equilibria of pure and mixed solvents of alkanolamines that are of relevance for carbon dioxide (CO₂) capture. Predictive approaches are essential when experimental data is limited, with the benefit that they become valuable approaches in the molecular and process design. The purpose of this work is the development of transferable intermolecular (square well SW) potential models that can be used within a group-contribution (GC) SAFT framework to identify mixtures that are good candidates for CO₂ absorption. The key advantage of the SAFT-γ GC-approach [1,2] is not only that the compounds of interest can be described in significant degree of molecular detail, but also the parameterization based on the contributions to the free energy of each like and unlike functional-group pair interactions can be transferred to a different compound that contains these common functional groups. The development of a molecular based model with transferable parameters is a key achievement compared to previous versions of the theory. In the proposed approach, we investigate the applicability of the SAFT-γ equation of state to study carbon dioxide, water and alkanolamine mixtures, and discuss how SAFT-γ opens avenues for thermodynamic property prediction, decreasing the dependence on experimental data. Systems that have been investigated include, but are not limited to primary and secondary amines and alcohols, and alkanolamines. Mixtures with amines are known to be very reactive and following earlier work [3], chemical equilibrium is treated here via a physical approach, so that reaction products are treated implicitly and their concentration in the mixtures is represented with appropriate Wertheim association schemes. We present calculations and predictions of the fluid phase behavior of these compounds and a number of their aqueous mixtures with and without CO₂.

References

[1] A. Lymperiadis, C. S. Adjiman, A. Galindo, and G. Jackson, J. Chem. Phys., 2007, 127, 234903.

[2] A. Lymperiadis, C. S. Adjiman, G. Jackson, and A. Galindo, Fluid Phase Equilib., 2008, 274, 85-104.

[3] J. Rodriguez, N. Mac Dowell, F. Llovell, C. S. Adjiman, G. Jackson, and A. Galindo, Mol. Phys., 2012, 110, 1325-1348.