Stimulation of CO2 solubility in reversible ionic liquids activated by novel 1-(2-aminoethyl piperazine) and bis (3-aminopropyl) amine

Abstract

The quest of energy efficient post combustion CO2 capture through an integrated process approach leads to the development of various novel solvents which can yield the necessary outputs. In line with this, the current work explores the experimental and simulation analysis of vapor liquid equilibrium of CO2 in novel aqueous 3-aminoproyl triethoxysilane (TESA) solvent blends enhanced by amine activators. Specific amine activators, viz. 1-(2-aminoethyl) piperazine (AEP) and bis (3-aminopropyl) amine (APA) were considered. The experiments were carried out over the temperature range of (303.2–323.2) K and pressure of (4–350) kPa. In order to realize the effect of activator, AEP/ APA concentration was gradually increased from 0.5 to 1.0 mol/kg with a total solvent concentration of ≈3 mol/kg. Along with this, qualitative 13C NMR and FTIR analysis were also performed to assess the proposed reaction scheme. The experimental vapour liquid equilibrium data (VLE) were correlated by modified Kent-Eisenberg equilibrium model considering gas phase non-ideality as well as non-rigorous statistical non-linear model. The equilibrium constants associated to deprotonation of protonated TESA, AEP and APA as well as carbamate formation reactions of these amines with CO2 are function of solvent concentration, temperature and CO2 partial pressure. These are regressed to fit the experimental VLE data. The modified KE model is further prolonged to estimate the concentration profiles of various molecular and ionic species involved in the reactive system.