Amino Acid Salts for Carbon Dioxide Capture: Evaluating l-Prolinate at Desorber Conditions

Abstract

Vapor−liquid equilibrium (VLE) measurements for unloaded and CO 2 -saturated aqueous potassium salt solutions of L-proline have been performed using a high-pressure equilibrium cell. The solubility of CO 2 has been determined at temperatures of 363, 393, and 403 K in 3 and 4 mol dm −3 aqueous solutions. The CO 2 partial pressures ranged from 3.0 to 358 kPa. In addition, the VLE data for CO 2 -free and CO 2 -saturated 3 mol dm −3 aqueous potassium sarcosinate solutions are presented for the same range of temperatures. The vapor pressures of the considered compounds have been determined at temperatures from 353 to 403 K. The reboiler duty required for stripping CO 2 from potassium L-prolinate solutions has been computed by the summation of the desorption enthalpy of CO 2 , sensible heat, and evaporation heat associated with co-produced regenerator overhead water vapor. A new approach to calculate the latter contribution is presented. The calculated energy requirements for L-prolinate are in the range reported in the literature for other amino acid salts.

Aqueous Potassium Lysinate for CO2 Capture: Evaluating at Desorber Conditions

“…These common features can also be observed in the other systems of CO 2 -amine-H 2 O and CO 2 - AAS-H 2 O. [12][13][14][15]20,21 The dependence of CO 2 partial pressure on the temperature and CO 2 loading in the temperature range studied for various concentration of LysK can be expressed by eq 5 as follows: 11,12,14…”

“…For aqueous absorbents, heat of water vaporization usually takes up 30−40% of the total regeneration energy. 12,23 Therefore, higher equilibrium pressure of CO 2 and lower partial pressure of water vapor in the gas phase at the outlet will reduce this part of energy required. 23 As for aqueous 47.2% LysK at 376 K, the large amount of CO 2 released and low volume of condensate water suggests that the ratio of partial pressure of CO 2 to H 2 O is higher than the other systems investigated, which results in the reduction of regeneration energy.…”

Characteristics of Potassium Prolinate + Water + Ethanol Solution as a Phase Changing Absorbent for CO2 Capture

“…16,17 Physicochemical properties are essential for kinetics of CO 2 absorption, simulation, and design of capture process. The solubility of CO 2 in aqueous amino acid salts such as lysinate, 12,13,18 prolinate, 12,14,15,19 and sarcosinate 9,10,20 has been widely reported recently. However, the data of density, viscosity, and CO 2 solubility for ProK/W/ Eth solutions have not been reported yet in literature.…”

“…However, the promising process using precipitating amino acid solvents for CO 2 capture has a limiting window of operation, where solid precipitation only occurred at higher concentrations and CO 2 partial pressures, for example, 4.0 M for potassium sarcosinate and 3.5 M for potassium prolinate at 293 K and 11.0 kPa CO 2 partial pressure. , Our latest study found that potassium prolinate + water + ethanol (ProK/W/Eth) solution as a novel phase-changing absorbent could easily enrich CO 2 into a solid phase with high absorption capacity and fast kinetics. , Physicochemical properties are essential for kinetics of CO 2 absorption, simulation, and design of capture process. The solubility of CO 2 in aqueous amino acid salts such as lysinate, ,, prolinate, ,,, and sarcosinate ,, has been widely reported recently. However, the data of density, viscosity, and CO 2 solubility for ProK/W/Eth solutions have not been reported yet in literature.…”

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

“…These studies − encouraged us to select and characterize a new blend of MDEA solution with an amino acid. Potassium or sodium salts of lysine, , sarcosine, proline, alanine, arginine, glycine, serine, phenylalanine, histidine, and taurine are the most widely studied amino acid salts for CO 2 absorption in the literature. Shen et al showed that potassium salt of lysine could be a good promoter due to its fast CO 2 absorption rate compared to most amino acids.…”