Study on the Formation Law of Natural Gas Hydrate in Nanobubble System

Summary The focus of this paper is on the formation law of natural gas hydrates in nanobubble systems. High-purity nanobubbles were prepared by in-situ decomposition of natural gas hydrates. The effects of different pressure reduction amplitudes, temperature rise amplitudes, and decomposition times on the concentration and size distribution of nanobubbles were investigated. Meanwhile, the effects of nanobubbles on the induction period, supercooling degree, and other characteristics of natural gas hydrate formation were analyzed. We found that the greater the pressure reduction and temperature rise amplitudes, and the longer the decomposition time, the higher the concentration of nanobubbles and the smaller their size. Nanobubbles with low dispersion (i.e., high concentration and small size) can significantly shorten the induction period of hydrate formation, reduce the supercooling degree, and have a more significant promoting effect on hydrate formation. Its mechanism of action includes enhancing gas/liquid mass transfer, increasing nucleation sites, and changing the thermodynamic properties of the system. This study provides a theoretical and experimental basis for the efficient regulation of natural gas hydrate formation.