For the low viscosity fluid of high-density polyethylene slurry polymerization reaction,using Maxblend impeller and three types of impeller combinations composed of three-blade-backswept impeller HQ150,parabolic disc turbine impeller BTD170,three blade hydrofoil impeller KHX170,pitched blade disc turbine impellers ZY160 with blade placement angle of δ=45°,and straight blade disc turbine impellers PY160,the gas-liquid dispersion and mass transfer characteristics in the air-water stirred tank were studied.Results indicate that the fitted empirical correlations of gas holdup,gas-liquid interfacial area and volume oxygen mass transfer coefficient are in good agreement with experimental data.The ratio of gassed power to ungassed power of the Maxblend impeller is least affected under aeration conditions,followed by the impeller combination 3.At an aeration rate of 0.6 vvm,the gas holdup of impeller combination 3 is the highest under the same power consumption.At high power,the d32 near the wall of impeller combination 3 is the smallest among impeller combinations 1,2 and 3.The impeller combination 3 exhibits the largest specific interface area,whereas the impeller combination 1 demonstrates the highest liquid-phase mass transfer coefficient.The mass transfer performance of impeller combinations 1,2 and 3 is almost the same,and are all better than that of the Maxblend impeller.
关键词
搅拌/功率消耗/气含率/气泡尺寸/气液传质
Key words
stirring/power consumption/gas holdup/bubble size/gas-liquid mass transfer
维普
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