Effect of Methylamine, Amylamine, and Decylamine on the Formation and Dissociation Kinetics of CO2 Hydrate Relevant for Carbon Dioxide Sequestration

Gas hydrates have been the nucleus of research from a sustainable engineering standpoint, considering their unique applications in a broad spectrum of scientific contexts. One such application is the sequestration of gaseous CO2 as solid hydrates under the seabed. Low temperature and high pressure are prevalent below the seabed, making it a thermodynamically feasible process. Furthermore, improved CO2 hydrate kinetics will facilitate technological development for carbon capture, storage, and sequestration. This study focuses on comprehending the CO2 hydrate kinetics with organic aliphatic amines, particularly methylamine, amylamine, and decylamine. Additives were tested in concentrations of 0.1, 1, and 5 wt % to meticulously comprehend their impact. A 300 mL stirred tank reactor was used for the investigations at 3.5 MPa and 274.55 K with pure water, which are the typical temperature and pressure conditions that one encounters in shallow subsea sediments. All additives showed considerable promotion in induction time, assuring faster CO2 hydrate nucleation. In addition, decylamine resulted in faster uptake of CO2 in our experiments compared to the other two additives. Hydrate dissociation studies up to 293.15 K were performed to assess the effect of the considered additives on CO2 hydrate dissociation. The decylamine system also delayed the gas release rate, showing better stability than the pure water system. This study also proposes a suitable well design for enhanced subsea CO2 sequestration as solid hydrates.