Effect of Coal Particle Size on the Kinetics of Gas Hydrate Formation

Coal and gas outbursts are one of the main factors that restrict access to high-quality coal, and the adoption of gas hydration solidification technology is expected to reduce the chance of such accidents. In this study, experiments were conducted on the kinetics of CH₄ and CO₂ hydrate formation in four coal particle size systems (C1:0.425-0.850 mm, C2:0.250-0.425 mm, C3:0.180-0.250 mm, and C4:0.150-0.180 mm). An experimental apparatus for high-pressure visualization of gas hydrate generation was used to obtain kinetic parameters such as gas consumption and the average growth rate during hydrate formation. The results showed that gas consumption and average growth rate of CO₂ hydrate decreased with decreasing coal grain size, while gas consumption and average growth rate of CH₄ hydrate decreased and then increased slightly with decreasing coal grain size, indicating that larger coal grains were beneficial to hydrate formation within a certain particle size range. The results of this research study are expected to provide an experimental reference for the development and application of technology for the solidification of gas hydrates to limit surges.