| Summary: | In order to identify the effect of the particle size of sediment media on the nucleation of gas hydrate (hereinafter referred to as hydrate), we conducted gas hydrate nucleation kinetics experiments on six types of sediment media by using the high-pressure visualized reactor to measure the nucleation induction time of hydrates in sediment media with different particle sizes, based on the size of hydrate-bearing sediments in the Shenhu sea area of the South China Sea. Besides, the nucleation pattern of hydrates in sediment media was analyzed using the probability distribution function. Then, considering the effect of capillarity on the liquid-gas interfacial tension in the pores of sediments, a theoretical model for the pore radius of sediment-nucleation induction time of hydrates was established based on the Kashchiev model in combination with the Arrhenius equation. Finally, the calculation results of the theoretical model were compared with the experimental results. The following results were obtained. First, sediment media with larger particle sizes can help effectively shorten the nucleation induction time of hydrate and increase the concentration degree of induction time. Second, it is deduced from the theoretical model formula that, due to the interfacial tension of pores in the sediment, the nucleation induction time of hydrate increases and then decreases with the increase of sediment particle size, and there is a critical particle size. Third, there is a non-positive correlation between the sediment particle size and the change of hydrate formation difficulty. Within a certain range, the hydrate formation difficulty decreases gradually with the increase of sediment particle size. The research results provide a technical support for the exploration of marine gas hydrate deposits. Keywords: Gas hydrate, Nucleation induction time, Sediment, Particle size, Pore, Capillarity, Induction time, Laboratory experiment
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