School of Civil and Environmental Engineering

Ph.D. Thesis Defense Announcement

Capture of CO₂ Using Potassium Salts of Amino Acids and Guanidine-Based Ligands

By Abishek Kasturi

Advisor:

Dr. Sotira Yiacoumi (CEE)

Committee Members:  Dr. Ameet Pinto (CEE), Dr. Costas Tsouris (CEE/Oak Ridge National Lab), Dr. Fani Boukouvala (ChBE), Dr. Radu Custelcean (Oak Ridge National Lab)

Date and Time:  Monday, December 11th, 2023, at 10am

Location: Monday, December 11th, 2023, at 10am  Zoom:  https://gatech.zoom.us/j/98345225537?pwd=Tk13VlNFK1BMVGM2K0ZZZnZiaFVmQT09

Meeting ID: 983 4522 5537

Passcode: 619879

 The concentration of atmospheric CO₂ has been steadily increasing since the industrial revolution, posing a significant threat to the global climate. The well-established correlation between rising anthropogenic CO₂ levels and climate change necessitates urgent action to reduce global carbon emissions. To mitigate the potentially irreversible consequences of climate change, deploying technologies capable of capturing CO₂ from point source emissions and the atmosphere is crucial. This thesis addresses knowledge gaps in flue gas-based capture and direct air capture of CO₂, focusing on the use of aqueous amino acids and phase-changing guanidines as promising alternatives.

Amino acids and guanidines exhibit favorable kinetics, negligible volatility, and lower energy requirements for regeneration compared to commonly used materials. To advance carbon capture, comprehensive understanding of the thermodynamics, kinetics, regeneration energy requirements, scalability potential, and costs associated with large-scale implementation is essential. This research involves thermodynamic and kinetic measurements to identify rate-limiting steps and cyclic capacities of amino acid and guanidine-based materials for carbon capture. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were employed to measure regeneration energy requirements, sensible heat, desorption enthalpy, and vaporization enthalpy.

Process-scale up potential was explored by intensifying the amino acid loading and guanidine crystallization steps. A novel gas-liquid contactor with high specific surface area, good wettability, high corrosion resistance, and moderate pressure drop was developed to enhance process intensification. Additionally, a technoeconomic analysis, based on experimental data and ASPEN modeling, estimated the energy requirements and costs of a scaled-up 1 Mt CO₂ direct air capture facility.

The information presented in this thesis is instrumental for implementing solvent-based carbon capture technologies, contributing to the global effort to combat climate change.