CO2 HYDRATE FORMATION KINETICS AND MODELLING OF THE AVAILABLE ENTHALPY OF CO2 HYDRATE SLURRY IN TANK REACTOR

The aim of this paper is to present the new results obtained in a conceptual design of a refrigeration system in which a hydrate forming gas/liquid mixture is used. The new circulation loop is equipped with a tank reactor allowing CO2-hydrate slurry to be studied. The results on CO2 hydrate formation kinetics showed that the undercooling degree decreases when the stirring velocity increases. Moreover, this study revealed that the kinetic varies in a range from 0.4 to 0.7 %.h(-1) for various stirring rates between 445 to 1340 rpm. These results allowed CO2-HS formation to be optimized. A first experimental approach based on chiller power measurements was carried out to evaluate the available enthalpy of CO2-HS. These results were compared to a theoretical model based on a mass balance on CO2 in its various phases (liquid, gas, hydrate) and allowing available enthalpy of CO2-HS to be calculate. The comparison between theoretical and experimental methods for the estimation of the available enthalpy of CO2-HS, applied to the first experiments in the tank reactor, is in good agreement.