In-situ de-cementation of cemented particles in a hydrocyclone for natural gas hydrate

Solid fluidization mining method is a promising method to develop natural gas hydrate, in which the in-situ separation of sand and hydrate particles is a key link. However, the presence of cemented particles will increase the difficulty of sand removal, leading to a decline in the sand removal efficiency of the hydrocyclone. This paper presents an experimental and a CFD-DEM coupling numerical study to investigate the movement behavior of these particles within the swirling field. The results show that with the increase of inlet velocity, the self-rotation and revolution velocities of cemented particles exhibit an increasing trend. At the same time, the tangential velocity gradient of the flow field gradually increases, which is conducive to achieving the de-cementation dispersion of cemented particles. The average normal force on cemented particles is greater than the normal cementation force, while the average tangential force on cemented particles is much less than the tangential cementation force. As the inlet velocity increases, the de-cementation efficiency increases obviously from 34.09% to 95.45%. This research provides theoretical guidance for the design and optimization of the hydrocyclone, which is conducive to promoting the green and safe development of natural gas hydrate.