Speedy Hydration of Carbon Dioxide Hydration in an Immediate Coolant of Ice Granules.

Abstract

Hydrate-based carbon capture (HBCC) has been considered as a promising technique in recent times. However, large exothermic heat of hydration and lower solubility of the gas in water cause a slower hydration rate and poor gas uptake during hydration. In the present work, a phase change heat removal method was applied, in which ice granules surrounded by normal alkanes were used as an immediate coolant and quick nucleation center to intensify the carbon dioxide capture through hydrate formation. Normal alkanes have great potential to enhance gas–water contact due to their high solubility with CO2 and thus may enhance the hydration rate. The slurries of ice in normal alkanes from cooling three different W/O emulsions were prepared to perform all the hydration experiments in a batch autoclave at a constant temperature of 267.15 K and pressure range of 1.9–2.5 MPa with a stirring speed of 600 rpm. Kinetics of CO2 hydrate formation such as induction time, hydration duration, molar gas uptake, and hydrate growth rate were determined using a mole balance (PVT) model. Compared to earlier investigations of hydrate formation, in present work, the hydrate growth rate increased by 7–39 times and enlarged to 352 times as compared to pure water while gas uptake per mole of water increased by 1.6–10 times.