162 / 2023-07-05 21:39:44

A study on the influence of micro-nano particleson gas hydrate formation kinetics and their potential: Application to the coal mine methane storage and transportation process

Coal mine methane; Methane hydrate; Micro-nanoparticles; Generation kinetics; Dissolution volume

As a safe, stable and environmental technology, the preservation and movement  of methane hydrate has a promising application in the reduction and use of coal mine methane (CH₄ is the main component). But the biggest obstacle to the industrialization of coal mine methane hydration technology is the sluggish kinetics of methane hydrate generation.Therefore, improving the kinetics of methane hydrate growth is a critical matter that requires attention. In this paper, 1 wt.% L-tryptophan and 0.3 wt.% gellan gum were used as the initial solution and different mass fractions (0 wt.%, 0.1 wt.%, 1 wt.%, 2 wt.%) of NiMnGa, coarse spherical Cu and COOH-MWCNTs (carboxylated multilayer carbon nanotub) were added to the suspension under the experimental conditions of 275.15 K and 6.2 MPa, respectively. ) micro-nanoparticles were prepared to form suspensions to investigate the effect on the kinetics of the growth process of methane hydrates. The results show that these micro-nanoparticles have a variable enhancement effect on methane hydrate formation. L-tryptophan + gellan gum + 2 wt.% NiMnGa had the most significant effect on methane gas consumption, compared to the L-tryptophan + gellan gum system without the addition of micro-nanoparticles, with a 7.68% increase in methane gas consumption; The fastest average generation rate was found for the L-tryptophan + gellan gum + 0.1 wt.% Cu system, with an increase of 16.87% compared to the L-tryptophan + gellan gum system. However, both gas consumption and average generation rate decreased linearly as the concentration of coarse spherical Cu micro-nanoparticles increased; At 289.15 K and 6.2 MPa, the 1 wt.% NiMnGa particles had a synergistic solubilisation effect with L-tryptophan and gellan gum, increasing the dissolved amount of methane by 41.63% compared to pure water, which was not the case for the other two micro-nanoparticles. Overall, this study provides guidance on selecting appropriate experimental conditions, micro-nanoparticle types and concentrations, and lays the foundation for the feasibility and sustainability of the hydrate method for storing and transporting methane.