CO_2 HYDRATE GROWTH MODEL AND RELATED EXPERIMENTAL DATA

摘要

CO_2 hydrate slurry have been proposed to be suitable for refrigeration application. In this study, the hydrate forming conditions are experimentally investigated. CO_2 hydrates are formed from CO_2 and water mixture at elevated pressures by cooling down the solution until a supersaturated condition is obtained. A theoretical crystal growth model is presented that will be used to predict the amount of hydrates produced in the experimental set-up. The previously developed flash model is used to predict the CO_2 concentration in the bulk liquid under super-saturation conditions. Equilibrium conditions, which are expressed through the equality of fugacities of each component in all phases, are assumed at the hydrate-liquid interface. The resulting concentration difference between bulk and interface is the driving force considered for the mass transfer from solution into the hydrate crystals. This will be combined with a simultaneous heat and mass transfer model and used in a control volume approach. This allows for the prediction of amount of crystal material formed as the solution flows through a coil heat exchanger.