Aqueous MAPA, DEEA, and Their Blend as CO₂ Absorbents: Interrelationship between NMR Speciation, pH, and Heat of Absorption Data

Abstract

Based on NMR speciation, heat of absorption and pH data, the reactions occurring in aqueous MAPA (3-(Methylamino)propylamine), DEEA (2-(Diethylamino)ethanol) and their blend at various carbon dioxide (CO2) loadings were identified and discussed. At increasing CO2 loading, the basicity of the solutions decreased. In the MAPA solvent, this led to the hydrolysis of the carbamate species, which corresponded to a drop in the heat of absorption. In the blend, due to the activity of DEEA, such a drop in both pH and heat of absorption was not noticeable. In the presence of MAPA, in the early loadings DEEA had not

Density, Viscosity, pH, Heat of Absorption, and CO2 Loading Capacity of Methyldiethanolamine and Potassium Lysinate Blend Solutions

“…Density and Viscosity. To evaluate the reliability of the density (g/cm 3 ) and viscosity (mPa•s) measurement procedure, the density and viscosity of MEA and K-Lys solutions at 298.15 K were measured and compared with the data reported in the literature. 14,40 The results presented in Table 2 indicate good agreement, ensuring the validity of the experimental data.…”

“…2 The selection of a suitable solvent is decisive to the techno-economic performance of a chemical absorption process. 3 An ideal absorbent should have high CO 2 absorption capacity, fast reaction rate, low toxicity and volatility, and high thermal and chemical stability along with low heat of absorption. 4 Aqueous methyldiethanolamine (MDEA) solution as a tertiary alkanolamine has advantages such as low heat of absorption, high thermal stability, low vapor pressure, and corrosion rate.…”

“…Although chemical absorption has been widely applied in industry for postcombustion CO 2 capture, technical and operational improvements such as development of new chemical solvents, integration of energy with other sections of the power plant, process flowsheet modifications, and parameter optimizations and utilization of alternative process configurations are still required to reduce the capital and operating costs of this method . The selection of a suitable solvent is decisive to the techno-economic performance of a chemical absorption process . An ideal absorbent should have high CO 2 absorption capacity, fast reaction rate, low toxicity and volatility, and high thermal and chemical stability along with low heat of absorption …”

Speciation in CO2-loaded aqueous solutions of sixteen triacetoneamine-derivates (EvAs) and elucidation of structure-property relationships

“…This will show if they meet the expectations, drawn from the relationships of the present work. Furthermore, there are still many influencing parameters which are unknown and which need to be studied, e.g., the effect chemical groups which were not part of the present work, or the influence of interactions between functional groups which are not part of the same molecule [19,28], which may lead to more new chemical structures or substituents of the ADAMs. If the ADAMs meet the expectations, still the complexity of their synthesis, the price of the molecules, their thermal and chemical stability, toxicity as well as further physico-chemical properties namely the dynamic viscosity of the aqueous solutions or the vapor pressure of the ADAMs have to be evaluated.…”

“…Determining the speciation of CO 2 -loaded aqueous solutions of amines means quantifying the amounts of protonated/unprotonated amine, bicarbonate and carbonate, carbamates, alkylcarbonates, molecular CO 2 , and eventually other compounds. The state of the art method for determining the speciation of CO 2 -loaded aqueous amine solutions is 1 H and 13 C NMR spectroscopy [17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34]. Other spectroscopic methods, such as Infra-red or Raman spectroscopy, have also been applied [35,36,37,38].…”