Methodologies for Non-aqueous Systems and Precipitating Systems as Carbon Capture Technologies: A case-study of AMP-NMP

Research output: ThesisDoctoral Thesis (compilation)

Abstract

In order to combat the effects of climate change, it is important to use a combination of solutions to achieve carbon neutrality as soon as possible. Carbon capture and sequestration is one such technology that can be used to significantly reduce the carbon footprint of many industrial plants. A mature technology for CO2 capture, amine-based post-combustion capture, is readily available today. However, the economic cost associated with CO2 capture plants constitutes a serious problem. Therefore, new systems are being developed in an attempt to reduce the cost of CO2 capture. Non-aqueous systems and precipitating systems are among the new systems being considered.
Research in such systems is still relatively new, and it will be several years before they can be applied commercially. The somewhat ambitious aim of the work presented in this thesis was to accelerate research in these fields by concentrating on methodologies that can be used in any non-aqueous systems (precipitating or non-precipitating) and precipitating systems (aqueous or non-aqueous). Two main research questions were posed to this end: 1) How can non-aqueous systems be modelled? and 2) How can the crystallization kinetics for gas-liquid-solid systems be estimated? Methodologies required to answer these questions were developed and tested for the case of the amine, 2-amino-2-methyl-1-propanol (AMP), in the organic solvent, N-methyl-2-pyrrolidone (NMP). This is a non-aqueous system and leads to precipitation when AMP reacts with CO2, i.e., it is also a precipitating system.
The system was modelled using an unsymmetric reference state of infinite dilution in water for ions. It was shown that using this for ions in non-aqueous solutions is thermodynamically valid, and it was applied to the AMP-in-NMP system. Experiments were performed to gain an understanding of the effect of equilibrium time, temperature, CO2 loading, and amine concentration on the solubility of CO2 in solution. These experiments were used to obtain the model parameters, and the model provided satisfactory predictions.
Regarding the crystallization kinetics, theoretical modifications to the semi-empirical power law relation are suggested in the cases of gas-liquid-solid equilibrium. The experimental procedure developed to estimate the crystallization kinetics was refined, and complications such as varying crystal structure are taken into consideration. The developed theory was assessed for the AMP-NMP system. The saturation conditions for the system, required in assessing crystallization kinetics, were obtained using the thermodynamic model developed in this thesis. Although developed for the case of AMP in NMP, the methodologies presented here for modelling thermodynamic behavior and crystallization kinetics can be extended to other non-aqueous systems and precipitating systems, respectively.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Other Engineering and Technologies not elsewhere specified

Keywords

  • CO2 capture, non-aqueous, precipitating, thermodynamic model, crystallization kinetics
Original languageEnglish
QualificationDoctor
Supervisors/Assistant supervisor
Award date2020 Feb 20
Publisher
  • Department of Chemical Engineering, Lund University
Print ISBNs978-91-7422-726-0
Electronic ISBNs978-91-7422-727-7
Publication statusPublished - 2020 Feb 4
Publication categoryResearch

Bibliographic note

Defence details Date: 2020-02-20 Time: 13:15 Place: Lecture hall K:B, Kemicentrum, Naturvetarvägen 14, Faculty of Engineering LTH, Lund University, Lund. External reviewer(s) Name: Mumford, Kathryn Title: Ass. Prof. Affiliation: University of Melbourne, Australia. ---

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