(74g) Thermodynamics in CO2 Capture By Chemical Absorption

One of the most important CO2 capture methods is the chemical absorption.  Amine-based solutions have been employed as absorbents to capture CO2.   Common shortcomings of these absorbents include high regeneration energy, toxicity and corrosive nature.   In this paper, we shall analysis the needs of new solvent from a thermodynamic view point. Thermal energy required for regeneration was broken down to desorption heat, sensible heat, and latent heat of solvent loss.   A quick screening experiments were introduced for testing new absorbent candidates by measuring absorption rate and capacity, heat capacity, desorption energy and solvent loss.   Aqueous solutions of a series of tetra-alkyl ammonium amino acid salts were evaluated and benchmarked against 30wt% monoethanolamine (MEA) solution.   They were selected because of their ability to reduce vapor pressure of water.  The results show that [N2222][L-Alanine] and [N1444][L-Alanine] both possess high absorption and desorption efficiency without precipitation problem.  The study illustrates the importance of thermodynamics consideration in guidng process development and how critical thermodynamic data can be used for benchmarking process alternatives.