(144c) Dynamics of Reactive Systems of Carbon Dioxide in Multifunctional Alkanolamines Using Thermodynamically Consistent Coarse-Grained Models with SAFT Mie Equation of State

The thermodynamics of the vapor-liquid equilibria of pure and mixed solvents of alkanolamines is of great relevance for carbon dioxide (CO₂) capture processes [1], but an equally important aspect is the dynamical behavior of CO₂ in such solvents. An accurate description of mass transfer is a key to the accurate developed of carbon capture absorption processes. Thus, by coupling together a predictive equation of state (EoS) for the thermodynamics and phase behavior together with robust coarse-grained models for use in explicit molecular simulation greatly enhance predictive solvent design for CO₂ capture processes. The advantage of such approach is that a molecular-based equation of state can be used to obtain effective coarse-grained models that reproduce the macroscopic experimental thermophysical properties over a wide range of conditions, while conventional molecular simulation with these coarse-grained models can be performed to obtain properties (such as structure or dynamics) that are not directly accessible with the EoS. The purpose of this work is the development of accurate coarse-grained models of aqueous mixtures of alkanolamines with and without CO₂ with the application of the statistical associating fluid theory of variable range (SAFT-VR) EoS with the Mie potential [2]. The newly developed coarse-grained models are then assessed based on their performance to both the dynamical behavior and the fluid-phase behavior for a number of alkanolamines and their aqueous mixtures with and without CO₂. Such an approach has been used successfully for a representation of the thermodynamic properties of CO₂ but the spherical model is not fully appropriate for the description of dynamical behavior [3]. Here we develop a non-spherical coarse grained model of CO₂which provides an accurate simultaneous description of both the thermodynamics and transport properties in complex solvents.

References

[1] N. MacDowell, N. Florin, A. Buchard, J. Hallett, A. Galindo, G. Jackson, C.S. Adjiman, C.K. Williams, N. Shah and P. Fennell, Energy Environ. Sci. 3, 1645 (2010).

[2] T. Lafitte, A. Apostolakou, C. Avendaño, A. Galindo, C. S. Adjiman, E. A. Müller and G. Jackson, J. Chem. Phys. 139, 154504 (2013).

[3] C. Avendaño, T. Lafitte, C. S. Adjiman, A. Galindo and E. A. Müller, and G. Jackson, J. Phys. Chem. B 117, 2717 (2013).