Improvement of CO2 hydrate formation and flow using chemical additives in a slurry loop and a stirred reactor: applications to refrigeration and CO2 capture

Secondary refrigeration and thermal energy storage techniques could be interesting solutions to improve refrigerating system performances and to reduce power consumption and propagation of refrigerants in the atmosphere. In order to combine a more efficient secondary loop and fluids with higher energy storage capacity, a phase change material (PCM) slurry, also called phase\nchange slurry (PCS), could be used as secondary refrigerant. In addition, hydrate-based processes could be an interesting option to separate the CO2 from various gas mixtures. In these two\napplications, the flow properties of the CO2 hydrate slurry are of paramount importance. In the present study, small amounts of Sodium Dodecyl Sulfate (SDS) were added to the aqueous phase,\nand this system was tested under CO2 pressure both in a dynamic flow loop and in a stirred reactor. The results obtained with the flow loop demonstrate that SDS has anti-agglomerant\nproperties for the CO2 hydrate: SDS significantly decreases agglomeration and thus improves flowing capacities of the slurry. The results obtained in the reactor shows that the presence of\nSDS increases the kinetics of the hydrate growth rate both in agitated and in quiescent hydrate forming conditions. Consequently, the addition of SDS could be very promising in industrial applications, such as secondary refrigeration or gas separation, where hydrate slurries must be easily handled and where the hydrate formation rate is of great importance.