Hanna Kierzkowska-Pawlak

Carbon Dioxide Removal from Flue Gases by Absorption/Desorption in Aqueous Diethanolamine Solutions

Abstract The carbon dioxide (CO2) desorption rate from CO2-loaded aqueous diethanolamine (DEA) solutions was measured using a stirred cell with a flat gas-liquid interface. The measurements were performed in the temperature range of 293.15–313.15 K and an amine concentration range of 10–20% mass DEA. Measurements were based on a semibatch isothermal absorption of the gas until the equilibrium state was reached, followed by desorption, which was initiated by the pressure release in the system. A simplified mass transfer model based on the film theory coupled with CO2 mass balance was developed to interpret the experimental data. On the basis of the proposed model, the initial mass transfer rates were calculated from the experimental results. The calculated initial desorption rates enabled estimation of the enhancement factor for CO2 mass transfer from aqueous DEA solutions. Analysis of the experimental data showed that desorption took place in the diffusive mass transfer regime.

Numerical simulation of CO2 absorption into aqueous methyldiethanolamine solutions

The CO2 absorption rate into aqueous N-methyldiethanolamine solutions was measured using a stirred cell with a flat gas-liquid interface. The measurements were performed in the temperature range of 293.15 to 333.15 K for various amine concentrations and CO2 partial pressures. A numerical model of mass-transfer with complex chemical reactions based on the film theory was developed to interpret the experimental results. The model predictions have been found to be in good agreement with the experimental values of CO2 absorption rates. A comparison is made between the enhancement factor predicted from the detailed model and the approximate solution of mass transfer equations with chemical reaction. The numerical results indicate that under the present experimental conditions, the effect of the reaction between CO2 and OH− on the observed mass transfer rates is negligible. The detailed mass transfer model was used for simulating the CO2 absorption process in terms of the enhancement factor under a variety of operating conditions.

Determination of Kinetics in Gas-Liquid Reaction Systems. An Overview

Determination of Kinetics in Gas-Liquid Reaction Systems. An Overview The aim of this paper is to present a brief review of the determination methods of reaction kinetics in gas-liquid systems with a special emphasis on CO2 absorption in aqueous alkanolamine solutions. Both homogenous and heterogeneous experimental techniques are described with the corresponding theoretical background needed for the interpretation of the results. The case of CO2 reaction in aqueous solutions of methyldiethanolamine is discussed as an illustrative example. It was demonstrated that various measurement techniques and methods of analyzing the experimental data can result in different expressions for the kinetic rate constants. Przegląd metod wyznaczania kinetyki reakcji gaz-ciecz Celem niniejszej pracy jest przegląd metod określania kinetyki reakcji gaz-ciecz ze szczególnym uwzględnieniem absorpcji CO2 w wodnych roztworach alkanoloamin. Omówiono zarówno homofazowe, jak i heterofazowe techniki eksperymentalne wraz z podstawami teoretycznymi niezbędnymi do interpretacji wyników. Jako przykład zinterpretowano wyniki własnych badań absorpcji CO2 w wodnych roztworach metylodietanoloaminy. Wykazano, że różne techniki pomiarowe i metody analizy danych doświadczalnych mają wpływ na otrzymaną zależność stałej szybkości reakcji od temperatury.

Investigation of CO2 and ethylethanolamine reaction kinetics in aqueous solutions using the stopped-flow technique

Kinetics of the reaction of CO2 and ethylethanolamine (EMEA) in aqueous solutions has been studied using the stopped-flow technique with conductivity detection. Measurements were performed at 288 K, 293 K, 298 K, and 303 K. Amine concentration ranged from 10 mol m−3 to 37.5 mol m−3. The termolecular mechanism was applied to interpret the kinetic data. In this mechanism, carbamate formation occurs in a single-step reaction without the formation of a zwitterion intermediate. An original method of analyzing the experimental data was proposed allowing the derivation of pseudo second order rate constants from the measured kinetic traces. Based on these values, the third order rate constants

Pressure swing absorption of carbon dioxide in n-methyl-2-pyrrolidone solutions

\left( {k_{H_2 O} } \right)

Kinetics of CO2 absorption in aqueous N,N-diethylethanolamine and its blend with N-(2-aminoethyl)ethanolamine using a stirred cell reactor

of the reaction of CO2, water, and EMEA were derived and correlated by the Arrhenius equation.

Kinetics of CO2 desorption from aqueous N-methyldiethanolamine solutions

Reaction Kinetics of Carbon Dioxide in Aqueous Diethanolamine Solutions Using the Stopped-Flow Technique The pseudo-first-order rate constants (kOV) for the reactions between CO2 and diethanolamine have been studied using the stopped-flow technique in an aqueous solution at 293, 298, 303 and 313 K. The amine concentrations ranged from 167 to 500 mol·m-3. The overall reaction rate constant was found to increase with amine concentration and temperature. Both the zwitterion and termolecular mechanisms were applied to correlate the experimentally obtained rate constants. The values of SSE quality index showed a good agreement between the experimental data and the corresponding fit by the use of both mechanisms. Kinetyka Reakcji Ditlenku Węgla w Wodnych Roztworach Dietanoloaminy z Zastosowaniem Techniki Zatrzymanego Przepływu W pracy przedstawiono wyniki badań kinetycznych reakcji CO2 w wodnych roztworach dietanoloaminy. Badania przeprowadzono z zastosowaniem techniki zatrzymanego przepływu w temperaturze 293, 298, 303 i 313 K, w zakresie stężeń aminy od 167 do 500 mol·m-3. Stwierdzono wzrost wartości stałej szybkości reakcji pseudopierwszego rzędu wraz ze wzrostem stężenia aminy oraz temperatury. Dane eksperymentalne zostały opisane za pomocą zależności kinetycznych wynikających z mechanizmu jonu dwubiegunowego oraz reakcji trójmolekularnej. Parametry kinetyczne dla obu mechanizmów wyznaczono w oparciu o minimalizację przyjętego wskaźnika jakości (SSE). Wartości tego wskaźnika wykazały dobrą zgodność pomiędzy danymi doświadczalnymi i odpowiednimi dopasowaniami z użyciem obu modeli kinetycznych.

Reaction kinetics of CO2 in aqueous methyldiethanolamine solutions using the stopped-flow technique

Pressure swing absorption of carbon dioxide in n-methyl-2-pyrrolidone solutions The mass transfer rates during CO2 absorption and desorption from N-methyl-2-pyrrolidone solutions were measured at 293.15 K in a baffled agitated reactor with a flat gas-liquid interface. Based on the measured values of pressure changes, the desorption rate was determined and compared to the absorption rate at the same driving force. Two distinct mechanisms of desorption were observed. The transition from bubbling to the diffusive desorption is found to be a function of the supersaturation ratio, pressure and the stirring speed.