Research progress on the effects of nanoparticles on gas hydrate formation

Abstract

Gas hydrate has great application potential in gas separation, energy storage, seawater desalination, etc. However, the intensity of mass and heat transfer is not enough to meet the needs of efficient hydrate synthesis. Nanoparticles, different from other liquid chemical additives, are considered as effective additives to promote hydrate formation due to their rich specific surface area and excellent thermal conductivity. This work summarizes the effect of the nanoparticles on the thermodynamics and kinetics of hydrate formation. And also, this work probes into the mechanism of the effect of the nanoparticles on the formation of hydrate as well as provides some suggestions for future research. It is found that it's difficult for nanoparticles to effectively promote the formation of the gas hydrate without the use of surfactants, because the adhesion characteristics of the nanoparticles make them easily agglomerate or even agglomerate in solution. In addition, at present, the research on the influence of nanoparticles on the formation and decomposition of natural gas hydrate is still very fragmented, and the micro mechanism of the influence is not clear, which requires more systematic and specific research in the future. At the same time, the development of nanoparticles that can promote the formation of natural gas hydrate should also become the focus of future research.

Fig. 1. Phase equilibrium of methane hydrate with or without MWCNTs (■: distilled water, □: 0.004 wt% MWCNTs).

Fig. 2. Phase equilibrium of tetrabutyl ammonium bromide (TBAB) + graphite nanoparticle (GN) varying with different GN concentrations.

Fig. 3. Comparison of the split fraction for the CO₂/H₂ hydrate formation with the synergic additives and other additives.