CO2 Hydrate Formation in SiO2/N-Tetradecane Phase Change Material Emulsion

Since hydrate-based CO2 storage is a new carbon sequestration technology, it is necessary to study the rapid growth and long-term stability of CO2 hydrates. In this study, SiO2 nanoparticles and N-tetradecane (phase change material, PCM) were utilized to improve the growth and stability of the CO2 hydrates. The effects of SiO2 nanoparticles and PCM on the formation of CO2 hydrates were investigated at a pressure of 5 MPa and temperature of 274.15 K. Compared with pure water, a slight increase in CO2 gas consumption was observed for phase change material emulsion (PCME) with SiO2 nanoparticles (SiO2/PCME) and it was 0.247 mol. The average gas consumption rate of CO2 in SiO2/PCME was increased from 0.058 to 0.086 mol/min since the addition of SiO2 nanoparticles was beneficial for the nucleation of CO2 hydrates and PCME can greatly enhance the heat transfer through absorbing the reaction heat of the hydration process. Besides, the decomposition of CO2 hydrates was prolonged from 81.5 to 125 min, so CO2 hydrates formed in SiO2/PCME had more stability. This study indicated that it is possible to store CO2 in the form of solid hydrates in geological reservoirs.