Experimental study of CO2 hydrate formation in porous media with different particle sizes

To investigate the effect of the particle size of porous media on CO2 hydrate formation, the formation experiments of CO2 hydrate in porous media with three particle sizes were performed. Three kinds of porous media with mean particle diameters of 2.30 mu m (clay level), 5.54 mu m (silty sand level), and 229.90 mu m (fine sand level) were used in the experiments. In the experiments, the formation temperature range was 277.15-281.15 K and the initial formation pressure range was 3.4-4.8 MPa. The final gas consumption increases with the increase in the initial pressure and the decrease in the formation temperature. The hydrate formation at the initial formation pressure of 4.8 MPa in 229.90 mu m porous media is much slower than that at the lower formation pressure and displays multistage. In the experiments with different formation temperatures, the gas consumption rate at the temperature of 279.15 K is the lowest. In 2.30 and 5.54 mu m porous media, the hydrate formation rates are similar and faster than those in 229.90 mu m porous media. The particle size of the porous media does not affect the final gas consumption. The gas consumption rate per mol of water and the final water conversion increase with the decrease in the water content. The induction time in 5.54 mu m porous media is longer than that in 2.30 and 229.90 mu m porous media, and the presence of NaCl significantly increases the induction time and decreases the final conversion of water to hydrate.