Acceleration of CO₂ Reaction with N,N-Diethylethanolamine in Aqueous Solutions by Piperazine

Abstract

N,N-Diethylethanolamine (DEEA), which can be prepared from renewable resources, represents a candidate alkanolamine for CO2 removal from gaseous streams. In this work, the reaction of CO2 with aqueous solutions containing N,N-diethylethanolamine (DEEA) was studied in a stirred cell reactor with a plane, horizontal gas−liquid interface, in the range of temperatures 298−308 K. The DEEA concentration in the aqueous solutions was varied in the range 2−3 kmol/m3. The liquid-side mass transfer coefficient and a combined parameter comprising the reaction rate constant and the diffusivity and solubility of CO2 in DEEA solutions were evaluated. The effect of the addition of piperazine (PIP) as a possible absorption activator was studied, and it was found that even with a small amount of PIP (0.1 kmol/m3) added, the CO2 absorption rate increased.

A Study on CO2 Absorption Kinetics by Aqueous Solutions of N,N‐Diethylethanolamine and N‐Ethylethanolamine

“…The reaction between CO 2 and DEEA in aqueous solutions was earlier studied by Kim and Savage [4] at 323 K, by Spaninks et al [5] at 303 K and by Benitez-Garcia et al [6] at 298 K. This reaction is of the first order with respect to both CO 2 and DEEA. Kinetic data at various temperatures were reported by Sotelo et al [7], by Littel et al [8] and recently by Li et al [3] and by Vaidya and Kenig [9,10]. Since there is no hydrogen atom attached to the nitrogen atom, as in the case of MEA and DEA, the carbamation reaction cannot take place.…”

“…2, provide a further check of our preliminary assumption of a fast pseudo-first-order reaction system. In our recent paper, we studied the kinetics of the CO 2 reaction with DEEA in aqueous solutions [10]. The enhancement factors (E M p ) for the CO 2 -DEEA system at 303 K and (DEEA) o = 2, 2.25 and 2.5 kmol/m 3 were determined from our earlier results and compared with those reported in Tab.…”

“…However, DEEA has low reactivity with respect to CO 2 due to its tertiary amine characteristics. We found that the second-order reaction rate constant attains a value of 173 m 3 /(kmol s) at 303 K [10]. The CO 2 absorption rate of an aqueous DEEA solution can be enhanced by the addition of an activator.…”

Advances in Liquid Absorbents for CO2 Capture: A Review

“…60 The potential of PZ as an activator in other CO 2 absorption solvents was also explored by Vaidya and Kenig using the additive in N,N-Diethylethanolamine (DEEA). 61 Typically, DEEA absorbs CO 2 relatively slowly, being a tertiary amine, but even with a small addition of PZ into DEEA, the CO 2 absorption rate significantly increased.…”

Influence of tert-amine groups on the solubility of polymers in CO2

“…According to the tabulated data, triethylamine has a donor number of DN [37,39]. It is important to note that unlike primary and secondary amines, tertamines do not form carbamate salts with CO 2 in the absence of water [40]. While such reactions may be desirable for the formation of surfactants upon reaction with CO 2 , our objective is the design of a polymer that dissolves in CO 2 without reacting with the CO 2 .…”