Study on Effect Factors for CO2 Hydrate Rapid Formation in a Water-Spraying Apparatus

To study effect factors on the rapid formation of CO2 hydrate, which has a high capacity for storage of CO2 to weaken global warming impacts, a specific visual water-spraying gas hydrate formation apparatus was designed. The gas consumption in the process of hydrate formation (in the initial pressure range of 2.1-3.5 MPa and initial temperature range of 1.5-3.0 degrees C) was observed, and the induction time, mole formation rate, and gas storage density within 1 h had been analyzed systematically under different gas supply modes, initial pressures, water volumes, and nozzle atomizing angles; also, the formation heat had been induced. Results showed that the hydrate formation rate, gas storage density, and total formation heat in the reactor were larger in the condition of the oscillating gas supply mode than continuous for the larger mass-transfer driving force caused by pressure disturbance in the former mode or, in a higher initial pressure, with a larger volume of water and nozzle atomizing angle. A larger volume of water in a reasonable range is beneficial for hydrate formation for a relatively larger dissolution quality, and a larger nozzle atomizing angle is also favorable because of higher gas liquid contact probability and larger contact area. Also, with a higher driving force, it can be realized that the morphology of hydrate particles transited from spherical to branching more quickly by the camera online observation of hydrate growth, for larger Gibbs free-energy differences of the phase transition.