Abstract:

Considering air-polyether polyols（PPG）as Gas-Liquid systems，the power consumption and gas holdup characteristics with two types of three-lay impellers were investigated in a stirred tank with elliptic bottom and internal diameter of 0.28 m at 20—120 ℃. The Relative Power Demand and gas holdup were correlationed for different multiple impellers. The results showed that gas holdup increases，while Relative Power Demand decreases along with the increase of gas flow rate and rotary speeds in the two impeller combination. As temperature increases，the two impeller combination gas holdup and Relative Power Demand reduce. However，multiple impellersⅠ（a half elliptical disk turbine，6-HEDT，at bottom and two up-pumping wide-blade hydrofoils ，WHu，above 6-HEDT）had better performance than multiple impellers Ⅱ（six inclined unseal turbine，6-XYK，at bottom，six inclined disk turbine，6-XDT，in middle and 6-HEDT at top）for its higher gas holdup and stirring power under the aerated condition and it was more suitable for the operation of gas-polyether polyols dispersion.