搅拌槽内多层组合桨对液-液分散特性的影响

Effect of multiple impeller agitators on liquid-liquid dispersion in a multi-impeller stirred tank

以水-煤油及水-环己烷为体系,研究Rushton涡轮桨(RT),半椭圆管涡轮(HEDT)及翼形轴流式桨(CBY)的6种不同组合桨的液-液分散特性。测定了不同输入功率时分散相体积分率沿轴向及径向的分布。结果表明:当搅拌槽内液位与槽径之比达1.5,在相同输入功率时,三层桨的液液分散性能优于两层桨,功率准数较低的CBY组合桨在输入功率0.8kW/m^3时,槽内的轴向及径向分散相体积分率达到稳定的均匀分布。而功率准数较大的RT组合桨需要在输入功率1.8kW/m^3才能达到槽内分散相的均匀分布。

The liquid-liquid dispersion was investigated in water-kerosene and water-cyclohexane systems. Six impeller combinations consisting of Rushton turbine (RT) , half elliptical disk turbine (HEDT) and three blade hydrofoil propeller (CBY) were used in the experiments. The axial and radial distributions of volume fraction of water and clarification times were measured at different input power. The results showed that the triple impellers were much better than dual ones in liquid-liquid dispersion when the liquid height-and-diameter ratio of the stirred tank was up to 1.5 at the same input power. The narrow-blade CBY combination offered homogeneous axial and radial distribution of volume fraction at input power of 0. 8 kW/m while the impeller combination with Rushton turbine offered homogeneous distribution at 1.8 kW/m3 input power.