Effects of Particle Sizes on Growth Characteristics of Propane Hydrate in Uniform/Nonuniform Sands for Desalination Application

Gas hydrate-based technology is of excellent prospects for seawater desalination and gas storage in development. The optimization of the hydrate growth process plays a pivotal role in improving technology efficiency. As a standard optimization method, porous media are widely used, and the effects of particle sizes on hydrate growth are still more investigated, especially the nonuniform type. In this study, the single-size uniform sands of 0.1, 0.2, 0.4, 0.6, and 0.8 mm and nonuniform mixed sands ranging from 0.08 to 2.00 mm were selected as porous media. The propane hydrate growth was investigated at an initial pressure of 0.48 MPa, temperature of 2 degrees C, and water saturation of 75% using a visual crystallizer. Visual observations indicate that the hydrate distribution was seen on the sand surface due to the upward migration of pore water by a capillary force. With the increase in the uniform sand size, the sand size can decrease the hydrate growth rate, and the size with the most hydrate growth amount above the sand surface is 0.4 mm. The small sand size of 0.1 mm mixed in two extensive areas of sand of sizes 0.6 and 0.8 mm can improve the kinetics of hydrate growth and increase the hydrates on the sand surface. In addition, the propane hydrate growth characteristics in nonuniform sands with mixed sizes are more similar to the uniform sand of 0.2 mm for their close diameter. Ultimately, the mixed sands with a diameter range of 0.2-0.4 mm are suggested as optimal porous media for propane hydrate-based desalination.

Automated summary

Gas hydrate-based technology shows great potential for seawater desalination and gas storage. This study found that the size of sand particles significantly affects the growth rate and amount of hydrates. By mixing sands of different sizes, the kinetics of hydrate growth can be improved, with mixed sands in the range of 0.2-0.4 mm diameter suggested as optimal porous media for propane hydrate-based desalination.