COSMO-RS Analysis of CO2 Solubility in N-Methyldiethanolamine, Sulfolane, and 1-Butyl-3-methyl-imidazolium Acetate Activated by 2-Methylpiperazine for Postcombustion Carbon Capture.

Sweta Balchandani,Ramesh Singh

doi:10.1021/acsomega.0c05298

Abstract

Novel aqueous (aq) blends of N-methyldiethanolamine (MDEA), sulfolane (TMSO2), and 1-butyl-3-methyl-imidazolium acetate ([bmim][Ac]) with amine activator 2-methylpiperazine (2-MPZ) are analyzed through conductor-like screening model for real solvents (COSMO-RS) for possible application in the chemisorption of CO2. The molecules associated are analyzed for their ground-state energy, σ potential, and σ surface. Thermodynamic and physicochemical properties have been assessed and paralleled with the experimental data. Vapor pressure of the blended systems and pure component density and viscosity have been compared successfully with the experimental data. Important binary interaction parameters for the aqueous blends over a wide temperature, pressure, and concentration range have been estimated for NRTL, WILSON, and UNIQUAC 4 models. The COSMO-RS theory is further applied in calculating the expected CO2 solubility over a pressure range of 1.0–3.0 bar and temperature range of 303.15–323.15 K. Henry’s constant and free energy of solvation to realize the physical absorption through intermolecular interaction offered by the proposed solvents. Perceptive molecular learning from the behavior of chemical constituents involved indicated that the best suitable solvent is aq (MDEA + 2-MPZ).

Highlights

The quest to reduce CO2 emissions via different routes has been a major concern over the past few decades
The appositeness of chosen solvents, i.e., MDEA, TMSO2, and [bmim][Ac], and their blends with 2-MPZ is determined using σ potential and σ surface analyses
The results indicate the suitability of 2-MPZ for a variety of solvents under study

Summary

Introduction

The quest to reduce CO2 emissions via different routes has been a major concern over the past few decades. The process intensification of the existing CO2 capture techniques and introduction of novel solvents for achieving the same through chemisorption or physisorption has been proposed by many researchers.[1,2] An extensive lab-scale development of vapor− liquid equilibria,[3] kinetic studies,[4] thermophysical properties,[5,6] calculation of binary interaction parameters,[7] improvement in the existing modeling techniques,[8] proposing new correlational analysis,[9] optimizing the reaction or process parameters,[10] defining the structural property relationships,[11] heat of absorption,[12] etc. COSMO-RS applications in the membrane separation processes through COSMOmic simulations have been widely studied in the recent past, indicating the efficiency of estimation of partition coefficients with fewer deviations from experimental studies in comparison to molecular dynamics simulation evaluations.[19−23]

Methods

Results

Conclusion