Thermodynamic and Kinetic Investigations of Clathrate Hydrates and Their Applications to CO2 Capture and Energy Gas Storage

Abstract

A clathrate hydrate is a class of inclusion compounds consisting of a host water framework formed by intermolecular hydrogen bonding, with guest molecules such as small gas and low molecular weight organic molecules. In this thesis, I investigated the thermodynamics and kinetics of various binary (organic + gas) clathrate hydrates using spectroscopic analysis to develop clathrate hydrates as functionalized materials for CO2 capture and energy gas storage. The thesis is structured into four main chapters. Chapter 1 introduces the general concepts of clathrate hydrates, including their structure classification, thermodynamics, and kinetics. Chapters 2 and 3 focus on clathrate hydrate-based CO2 capture. Chapter 2 covers clathrate hydrate-based post-combustion CO2 capture using 3,3-dimethyl-1-butanol (DMB) molecules, with a focus on the structural transformation and instability of structure H hydrate. Chapter 3 covers clathrate hydrate-based pre-combustion CO2 capture using various wettability silica gels, with a focus on the separation mechanisms and performance. Based on the results, a novel efficient 3-stage reactor process for pre-combustion CO2 capture is proposed. Chapter 4 focuses on clathrate hydrate-based natural gas storage using the tuning effect. The tuning effect of sH clathrate hydrate with CH4 molecules is demonstrated for the first time. The dominant factors inducing the tuning phenomena are revealed using in-situ Raman spectroscopy, and improving the gas storage capacity in bulk hydrate systems using the tuning effect is demonstrated. Based on the results, a feasible strategy to design an efficient tuning hydrate-based natural gas storage system is proposed. Overall, the thesis provides insights into the thermodynamic and kinetic properties of binary clathrate hydrates and their potential applications in CO2 capture and energy gas storage. The findings highlight the importance of developing functionalized clathrate hydrates and provide insights for future research of clathrate hydrates.