针对固态流化开采方法开采海底天然气水合物含砂量大导致开采效率低的问题，提出原位分离工艺，设计了旋流分离装置，基于该装置利用CFD数值模拟方法研究了固相(砂和水合物颗粒)直径、入口浆体流量及浆体中砂浓度对装置分离性能的影响。结果表明，在研究范围内，砂和水合物分离效率大部分高于60%，最高达98.72%，压降大部分低于0.5 MPa，最低至0.03 MPa。砂粒分离效率随固相粒径增大先增大后趋于平稳，随浆体入口流量增大先增大后减小，随砂浓度增大而降低；水合物分离效率随固相粒径增大先增大后趋于平稳，随浆体入口流量增大先增大后减小，随砂浓度增大而降低。溢流口和底流口压降几乎不随固相粒径变化，随砂浓度和浆体入口流量增大而增大。固相粒径、入口流量、砂浓度对分离性能有较大影响，在砂粒径大于20 ?m、水合物粒径大于40 ?m、浆体入口流量约5 m3/h、入口砂浓度不超过25vol%的条件下分离性能良好。
In view of the problem of low efficiency caused by the large amount of sand contained in the natural gas hydrate of the seabed in process of hydrates mining in the solid-state flow method, a novel separation process was presented based on the solid fluidization, and a hydrocyclone used for submarine gas-hydrate slurry was designed based on the properties of seabed gas-hydrate and the multiphase flow theory. The effects of particle (sands and gas-hydrate) size, inlet flux of slurry, and sands concentration in gas-hydrate slurry on separation efficiency and pressure drop were simulated by CFD. The results showed that the separation efficiencies of sand and gas-hydrate were more than 60%, and the maximum was 98.72%, the pressure drop was within 0.5 MPa, and the lowest was 0.03 MPa with the hydrocyclone at the conventional condition. The separation efficiency of sand increased first and then unchanged when particle size was increased. When inlet slurry flux was increased, the sand separation efficiency first increased and then decreased. When sand concentration in slurry was increased, the separation efficiency was always decreased. The separation efficiency of gas-hydrate increased first and then unchanged with increasing particle size and inlet slurry flux. When increasing sands concentration in slurry, the separation efficiency of gas-hydrate was decreased. The pressure drops in the overflow and underflow outlet were almost unchanged when particle size was increased, and increased with the sands concentration in slurry and inlet slurry flux increased. It was revealed and verified that the particle size, inlet slurry flux, and the sand concentration had great influence on the performance of the hydrocyclone. The separation performance was very good when the sand size was greater than 20 ?m, the hydrate size was greater than 40 ?m, the inlet slurry flux was about 5 m3/h, and the sand concentration was no more than 25vol%.
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