Experimental Measurement of Carbon Dioxide Solubility in Aqueous N-Methyldiethanolamine + 2-(2-Aminoethylamino) Ethanol + Sulfolane and Diethanolamine + 2-(2-Aminoethylamino) Ethanol + Sulfolane Hybrid Solvents at Various Temperatures and High Pressure

Abstract

The sets of vapor–liquid equilibrium (VLE) data for CO2 solubility in a combination of (N-methyldiethanolamine (MDEA) + 2-(2-aminoethylamino) ethanol (AEEA)) and (diethanolamine (DEA) + AEEA) as a chemical solvent blended with sulfolane as a physical solvent are acquired at 313.15–343.15 K within the CO2 partial pressure range up to 5600 kPa. The measurements are fulfilled for two different hybrid solvents of MDEA + AEEA + sulfolane with the weight compositions of (20–10–10) wt % and (20–10–20) wt % and a mixed solvent of DEA + AEEA + sulfolane with (20–10–10) wt %. It is deduced that CO2 loading was enhanced by substituting the MDEA with DEA, diminishing the temperature, and raising the pressure. Besides, increasing the sulfolane concentration in the aqueous system of MDEA + AEEA + sulfolane leads to enrichment in the effectiveness of the solution in CO2 absorption in the high loading region. In contrast, at low pressures, it adversely affects the acid gas loading. Moreover, it was displayed that at the same total mole of alkanolamines and sulfolane, the CO2 solubilities of AEEA + sulfolane and AEEA + MDEA + sulfolane are higher than those of AEEA + MDEA + sulfolane and MDEA + sulfolane, respectively. Therefore, it could be claimed that AEEA presents a better performance in CO2 capturing than MDEA. Besides, it was demonstrated that AEEA + sulfolane represents a higher capability in CO2 elimination than DEA + AEEA + sulfolane. Thus, the ability of DEA to remove CO2 is lesser than AEEA. Altogether, the degree of alkanolamines’ selectivity toward CO2 is found as AEEA > MDEA > DEA.

High-Pressure Vapor–Liquid Equilibrium Measurement of CO2 Solubility into Aqueous Solvents of (Diisopropylamine + L-Lysine) and (Diisopropylamine + Piperazine + L-Lysine) at Different Temperatures and Compositions

“…We attached a calibrated thermocouple (model ST-612, Standard Instrument Co. Ltd., Hong Kong) to this gas-storage vessel to display its temperature accuracy of ±0.1 K. Moreover, to determine the pressure, we equipped the injection cell with the same 0–10,000 kPa calibrated pressure transducer (model 33X, Keller, Switzerland) with uncertainties of 1.75 kPa. It should be mentioned that the manufacturers of these measurement tools have quantified the various instruments’ precisions of the present setup . Moreover, a vacuum pump (model DV-142 N-PLATINUM 5 CFM, JB Company, USA) was used for the equilibrium high-pressure cell’s depletion.…”

“…It should be mentioned that the manufacturers of these measurement tools have quantified the various instruments' precisions of the present setup. 31 Moreover, a vacuum pump (model DV-142 N-PLATINUM 5 CFM, JB Company, USA) was used for the equilibrium high-pressure cell's depletion. This apparatus is connected to a CO 2 cylinder for charging gas to the injection cell.…”

“…Figure 1. Schematic diagram of high-pressure vapor−liquid equilibrium experimental equipment applied in this research for measurement of the single gas solubility into the various blends of amino acid and alkanolamines at different concentrations and elevated pressure: (1) a cylinder which contains acid gas, (2) regulator, (3) the gas-storage vessel, (4) high-pressure autoclave, (5) solvent reservoir, (6) a magnetic stirrer, (7) thermostatic circulator, (8) vacuum pump, (9) a unit for monitoring, (10) personal computer (PC), (11−13) pressure transducers, (14) pressure indicator, (15) temperature sensor (Pt-100), (16−25) valves, (26) drain valve 31. …”

The Ratio of Chemical and Physical CO2 Absorption Capacity in Triethanolamine and Methyl-diethanolamine Solution Systems

“…Idem et al stated that the energy consumed for solvent regeneration in an MDEA/MEA hybrid system was less than that consumed by an MEA system . In addition, there have been many works examining CO 2 solubility and its equilibrium in TEA and MDEA systems at various temperatures and CO 2 partial pressures, − and most of them primarily focused on increasing the overall CO 2 absorption performance of the systems. However, no studies have reported the quantitative individual amount of CO 2 chemically absorbed by amine and physically absorbed by water relative to the total absorption capacity, which can be calculated in TEA and MDEA systems.…”