溢流管结构对天然气水合物用旋流器分离性能的影响

Effect of vortex finder structure on the separation performance of hydrocyclone for natural gas hydrate

建立了主直径100 mm的旋流器模型,采用计算流体力学(CFD)方法研究了溢流管内径、插入深度及壁厚对旋流器分离天然气水合物性能的影响规律。结果表明,入口流速为9m/s时,随溢流管内径增大,水合物分离效率增大,砂的分离效率降低,旋流器的压力降逐渐减小;随溢流管壁厚增大,水合物和砂的分离效率稍有增大,旋流器的压力降先增大后减小;随溢流管插入深度增大,水合物分离效率先减小后增大,砂的分离效率先增大后减小,旋流器的压力降波动较小。溢流管内径对旋流器分离天然气水合物性能的影响最大,插入深度次之,壁厚的影响最小。

In the view of the problems of pipeline jam,tools erosion and high energy consumption in pipeline transportation caused by the slurry with high content of sand in the process of the solid fluidized mining for the non-diagenetic natural gas hydrate in the shallow seabed, the downhole hydrocyclone has been designed for in-situ desanding and purification of hydrate slurry. The vortex finder is an important structure of hydrocyclone, which greatly affects the separation performance of the hydrocyclone. The hydrocyclone model with nominal diameter of 100 mm and computational fluid dynamics(CFD) numerical method were used to study the influence of vortex finder structure on separation performance of hydrocyclone. The results showed that under the condition of 9 m/s inlet flow rate, the separation efficiency of gas hydrate increased with inner diameter, on the contrary, the separation efficiency of sand decreased. The pressure drop of hydrocyclone decreased gradually with the increase of inner diameter. The separation efficiencies of gas hydrate and sand increased slightly with wall thickness, while the pressure drop of hydrocyclone increased firstly and then decreased with the increase of wall thickness. It was concluded that the separation efficiency of gas hydrate decreased firstly and then increased, while the separation efficiency of sand increased firstly and then decreased, and the pressure drop of hydrocyclone had been less affected. The inner diameter had the greatest influence on the separation performance of hydrocyclone for gas hydrate, followed by the insertion depth of vortex finder, and the wall thickness of overflow tube had the least influence on the separation performance of hydrocyclone. The research work had certain guiding significance for the field application of hydrocyclone in gas hydrate exploitation.