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Hanna Kierzkowska-Pawlak

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.

Open access

Hanna Kierzkowska-Pawlak

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.

Open access

Marta Siemieniec, Hanna Kierzkowska-Pawlak and Andrzej Chacuk

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.

Open access

Hanna Kierzkowska-Pawlak, Marta Siemieniec and Andrzej Chacuk

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

The kinetics of the reaction between CO2 and methyldiethanolamine in aqueous solutions have been studied using the stopped-flow technique at 288, 293, 298 and 303 K. The amine concentration ranged from 250 to 875 mol·m-3. The overall reaction rate constant was found to increase with amine concentration and temperature. The acid base catalysis mechanism was applied to correlate the experimentally determined kinetic data. A good agreement between the second order rate constants for the CO2 reaction with MDEA computed from the stopped-flow data and the values reported in the literature was obtained.

Open access

Ewelina Kruszczak and Hanna Kierzkowska-Pawlak

Abstract

The CO2 absorption process using aqueous amine solutions has been the most promising technique used for the removal of CO2 from gas streams in energy sector. In recent years, many researchers tested solutions which are composed of several compounds: a slow reacting tertiary amine- and a fast amine acting as an activator. In this paper, the CO2 absorption rate in an aqueous solution of N,N-diethylethanoloamine (DEEA) and activated solutions DEEA is investigated experimentally. The activators considered are sterically hindered amines: 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-methyl-1,3-propanediol (AMPD) and N-methyl-1,3-propanediamine (MAPA) from the group of polyamines. The experiments were conducted over the temperature range of 303-333 K and the total amine concentration of 2 M. From the CO2 absorption experiments into mixed aqueous solutions of DEEA and MAPA, it was found that the addition of small amounts of MAPA into aqueous DEEA solutions has a significant effect on the enhancement of the CO2 absorption rate. The application of hindered amines: AMP or AMP as activators resulted in a marginally improvement of the absorption rate of CO2.

Open access

Andrzej Wilk, Lucyna Więcław-Solny, Dariusz Śpiewak, Tomasz Spietz and Hanna Kierzkowska-Pawlak

Abstract

Amine absorption processes are widely used in the industry to purify refinery gases, process gases or natural gas. Recently, amine absorption has also been considered for CO2 removal from flue gases. It has a number of advantages, but there is one major disadvantage - high energy consumption. This can be reduced by using an appropriate sorbent. From a group of several dozen solutions, three amine sorbents were selected based on primary, tertiary and sterically hindered amines. The solutions were used to test CO2 absorption capacity, absorption kinetics and heat of CO2 absorption. Additional tests were performed on the actual absorber-desorber system to indicate the most appropriate sorbent for capturing CO2 from flue gases.