Continuous Formation of CO2 Hydrate via a Kenics-Type Static Mixer

Formation of CO 2 hydrate using a Kenics-type static mixer was studied experimentally. The flows of liquid CO 2 and water were mixed in the static mixer, and CO 2 hydrate was formed continuously from the two-phase flow. The patterns of hydrate formation were found to be dependent on the flow velocities of liquid CO 2 and water. The flow of agglomerated hydrate chunks in water occurred under relatively CO 2 -rich conditions, while dispersed flow of tiny particles of CO 2 hydrate with small liquid CO 2 drops was observed under relatively water-rich conditions. These effects could be explained by two mechanisms occurring in the static mixer, namely, continuous shedding of hydrate films from the interface between liquid CO 2 and water induced by the shearing force and breakup of the CO 2 drops. The energy consumption by the static mixer for the hydrate formation process was estimated, and it was significantly less than that for a stirring vessel type reactor. A continuous hydrate formation process could be achieved using the static mixer.