Application of KHX Impeller in a Low-shear Stirred Bioreactor

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 this work, the KHX impeller was applied in a lower-shear bioreactor and the performance of this reactor was evaluated and compared with that of the PBTD impeller. The experimental results show that 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.

Graphical AbstractWith the KHX impeller in a gas–liquid–solid stirred reactor, greater values of kLa and better gas dispersion performance were obtained compared with the PBTD impeller at the same power consumption. The KHX impeller has much wider impeller blades and can break bubbles sufficiently. Besides, the values of kLa are higher with a draft tube because the local density of power consumption in the impeller zone is greater than that without a draft tube, leading to better gas dispersion.Figure optionsDownload full-size imageDownload as PowerPoint slide