Abstract: In our previous work, a low-shear stirred bioreactor was explored. With a pitched blade turbine impeller downflow (PBTD) used, the shear stress generated is high compared with that in some low shear axial flow impellers. KHX impeller is an efficient axial flow impeller, which provides large onflow diffusivity and low shear force. In thiswork, the KHX impellerwas applied in a lower-shear bioreactor and the performance of this reactor was evaluated and comparedwith that of the PBTD impeller. The experimental results showthat the KHX impeller can disperse gas at lower power consumption and gives greater gas-liquid volumetric mass transfer coefficients than PBTD at the same power consumption. An empirical correlation for evaluating the mass transfer coefficient of the KHX impeller in the bioreactor is presented to provide reference for its industrial application.

Key words: Bioleaching reactor, Draft tube, Mass transfer coefficient, Ore suspension, Shear stress

摘要： In our previous work, a low-shear stirred bioreactor was explored. With a pitched blade turbine impeller downflow (PBTD) used, the shear stress generated is high compared with that in some low shear axial flow impellers. KHX impeller is an efficient axial flow impeller, which provides large onflow diffusivity and low shear force. In thiswork, the KHX impellerwas applied in a lower-shear bioreactor and the performance of this reactor was evaluated and comparedwith that of the PBTD impeller. The experimental results showthat the KHX impeller can disperse gas at lower power consumption and gives greater gas-liquid volumetric mass transfer coefficients than PBTD at the same power consumption. An empirical correlation for evaluating the mass transfer coefficient of the KHX impeller in the bioreactor is presented to provide reference for its industrial application.

关键词: Bioleaching reactor, Draft tube, Mass transfer coefficient, Ore suspension, Shear stress