Lieber, Austin Reed and Hornbostel, Katherine and Bedewy, Mostafa and Zhao, Xiayun
(2024)
Multiphysics Investigations of Emerging Direct Air and Ocean Carbon Capture Technologies.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
This thesis aims to advance the diverse fields of carbon removal through the experimental and computational applications of available and emerging materials and processes. Current oceanic and terrestrial carbon dioxide removal strategies span a wide range of technologies supported by biological and nonbiological mechanisms. This thesis organizes the current industry strategies for carbon dioxide removal and expands upon those featuring membrane and solid adsorbent separation mechanisms. First, a literature review organizes the landscape of carbon dioxide removal by analyzing each strategy and its energy costs and infrastructural requirements for deployment. A comparison of these strategies, their current and future challenges, and potential benefits is offered. This review highlights the elevated costs of certain nonbiological carbon dioxide removal strategies and motivates research on membrane- and adsorbent-based carbon separation mechanisms. Second, an investigation is conducted on the feasibility of using membrane-encapsulation of CO$_2$ solvents to remove dissolved unionized carbon dioxide from seawater. This investigation involved a series of lab-scale experiments that guided the development of 0D and 1D computational models. These computational models then informed a preliminary techno-economic assessment, which found that the economic feasibility of microencapsulated solvents for ocean carbon dioxide removal was limited. The investigation concluded that the financial viability of this strategy is more realistic when seawater pH is lowered by 2-3 orders of magnitude, suggesting the need for advanced membrane coatings development to realize this end. Finally, an investigation is conducted using hierarchically structured metal-organic frameworks (MOFs) as core-shell pellets for atmospheric carbon dioxide removal in the presence of ambient humidity. This highly collaborative MOF investigation combined experimental adsorption isotherm data with computationally derived theoretical selectivity and diffusivity values into a 2D parametric simulation of a core-shell MOF pellet. This model included five distinct variants of the (Zr)UiO-67 MOF and parameterized the pellet's shell thickness, ambient humidity levels, and carbon dioxide concentrations to arrive at optimized operation conditions. This investigation found that the pellet's shell was most effective at separating water from carbon dioxide before reaching the pellet's core when the shell MOF's linker had a more hydrophilic character. A thicker pellet shell increased the degree of separation between these two gases but also necessarily led to extended CO$_2$ saturation times and reduced capacity. This study concludes with the need for more comprehensive experimental and computational research to facilitate simulation accuracy and reliability. Furthermore, continued efforts to replicate this work will enable the establishment of best-use cases for such hierarchically structured materials in the carbon removal sector.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
3 June 2024 |
| Date Type: |
Publication |
| Defense Date: |
2 April 2024 |
| Approval Date: |
3 June 2024 |
| Submission Date: |
5 April 2024 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
124 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering and Materials Science |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
microencapsulated sodium carbonate, carbon capture and removal, gas separation, ocean capture |
| Related URLs: |
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| Date Deposited: |
03 Jun 2024 14:43 |
| Last Modified: |
03 Jun 2024 14:43 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/46040 |
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