▎ 摘　　要

Gas hydrate technologies are gaining interest in industries concerned with the transport and storage of natural gas. Graphene nanoflakes (GNFs) have been shown to improve the properties of methane hydrate-forming solutions, and nitrogen-doped GNFs (N-GNFs) may further these promotional effects. In this study, the dissolution rates of methane and molar saturation values at 2 degrees C and 3146 kPa, as well as methane hydrate growth rates at 2 degrees C and 4646 kPa, were measured in nanofluids containing N-GNFs with both low (4.28 at. %, LN-GNFs) and high (17.41 at. %, HN-GNFs) levels of doping. Loading effects for these systems were determined, and comparisons made with previous studies of as-produced GNFs (non-doped, AP-GNFs). The addition of nanoparticles had no thermodynamic effect on the system: the molar saturation value did not change at any loading. Dissolution rates were determined to be 17.54% faster for LN-GNF solutions and 21.21% faster in HN-GNF solutions compared to the pure water baseline. At lower loadings, LN-GNFs enhanced dissolution rates 2% more compared to AP-GNFs while HN-GNFs enhancement was 7% higher. However, at higher loadings, all three nanoparticles had similar levels of enhancement. Loading effects were attributed to higher N-GNF surface energy, which would improve their dispersion through greater repulsive forces but also give them a significant propensity to agglomerate at higher loadings such that the excess Gibbs free energy of the system is reduced. Hydrate growth rates were also enhanced by 77.20% for LN- and 38.32% for HN-GNFs. Compared to AP-GNFs, LN-GNFs had similar enhancement at low concentrations in clathrate-forming systems, but enhancement was about 29% lower (growth rates were 29% slower) in the higher loading regime. HN-GNFs consistently showed rate enhancements that were about 47.5% lower on average. This diminished enhancement could have resulted from the greater effective N-GNF concentration coupled with their higher propensity to agglomerate.