Absorption of CO₂ in Aqueous Diglycolamine

Abstract

Absorption of CO 2 into aqueous DGA (Diglycolamine) was performed at 25-60 °C in a wetted-wall column. The absorption data were analyzed using a rigorous model based on eddy diffusivity theory and approximations assuming pseudo-first-order (PFO) and interface pseudo-first-order (IPFO) reactions. The PFO is a good approximation for CO 2 absorption into DGA at a CO 2 loading of less than 0.2 mol/mol DGA. At CO 2 loadings greater than 0.4, instantaneous reactions are approached. The IPFO model matches the rigorous model very well. The second-order rate constant in 65 wt % DGA at 25 °C for the reaction with CO 2 is four times larger than previously published values, but 25 wt % DGA yields a rate constant which is in good agreement with literature values. This finding suggests that the second-order rate constant is probably a function of DGA concentration. The second-order rate constant in 65 wt % DGA increases by a factor of 5 from 0 to 0.4 mol CO 2 /mol DGA. Experiments with 65 wt % DGA + glycolic acid and 65 wt % DGA + potassium formate at 25 °C and 40 °C showed similar trends. The rate constant increases a factor of 2 to three in these solutions, suggesting that the rate constant is a function of ionic strength.

CO2‐Alkanolamine Reaction Kinetics: A Review of Recent Studies

“…Previous studies on the absorption of CO 2 by an aqueous DGA solution, which are outlined by Versteeg et al [6], suggest that the overall reaction order has a value of two. The reaction rate constant (6660 m 3 / (kmol s)), reported by Al-Juaied and Rochelle [22] at low concentration (25 wt % DGA) and at 298 K, is in agreement with the values available in literature. However, at high concentration (65 wt % DGA), the rate constant was four times larger than the previously published values, thereby suggesting its dependence on the DGA concentration.…”

“…Another primary amine -DGA -was recently studied by Al-Juaied and Rochelle [22]. Previous studies on the absorption of CO 2 by an aqueous DGA solution, which are outlined by Versteeg et al [6], suggest that the overall reaction order has a value of two.…”

CO2 Capture Using Monoethanolamine in a Bubble‐Column Scrubber

“…With a structured packing, the overall mass transfer coefficients reported by Arnoowilas et al [39] were in the range of 0.21-0.90 s -1 . In addition, mass transfer coefficient data from the batch-mode bubble columns were 0.005-0.10, 0.045-0.085, 0.01-0.15, and 0.02-0.14 s -1 as reported in [34][35][36]40].…”

“…Operating conditions and measured data obtained in this work. [24,[34][35][36][37]. Other evaluated output data, such as removal efficiency, absorption rate, overall mass transfer coefficient, and scrubbing factor, are also listed in Tab.…”

Characterization of potassium glycinate for carbon dioxide absorption purposes

“…In the last decades, hollow fiber membrane contactors have been studied using absorbent aqueous solutions such as alkanolamines or blends of alkanolamines for the selective removal of acid gases like H 2 S and CO 2 from a variety of industrial and natural gas streams (Al-Juaied and Rochelle, 2006;Kumar et al, 2003a). However, for applications in highly oxygenated environments, such as flue gas treatment, life support systems or anesthetic gas circuits, alkanolamines might not be of interest since they undergo oxidative degradation (Goff and Rochelle, 2006;Kumar et al, 2003c;Supap et al, 2006).…”