Assessment of the gas discharge characteristics during gas recovery by hydrate decomposition

Hydrate-based gas separation is a novel approach for the capture and recovery of hydrofluorocarbons. The gas discharge characteristics during hydrate decomposition need to be clarified for the efficient recovery of hydrofluorocarbons. In this study, we investigated the mass transfer characteristics during the gas recovery from hydrate particles by decomposing the HFC134a hydrates. First, the volumetric mass transfer coefficient was estimated from the gas recovery rate during the HFC134a hydrate slurry. The hydrate particles enhanced the gas recovery performance of the overall apparatus. Next, the mass transfer coefficient between hydrate and liquid was calculated. Ascending bubbles and the resulting change in the dispersion state of the particles significantly affected the mass transfer. Finally, we developed a mass transfer correlation equation between the solid and liquid phases by dimensionless numbers based on Kolmogorov’s theory. The experimental equation predicted the Sherwood number with ±40 % accuracy and an average absolute relative error of 19.0 %. The dispersion state of the hydrate particles was a significant factor in the estimation. [Display omitted] •Gas discharge during HFC134a hydrate decomposition was investigate.•Ascending bubbles enhanced the gas recovery performance.•An experimental equation to predict the mass transfer rate was developed.•The dispersion state of the particles is an important factor for the mass transfer.