Experimental and CFD-PBM Study of Oxygen Mass Transfer Coefficient in Different Impeller Configurations and Operational Conditions of a Two-Phase Partitioning Bioreactor

详细信息    查看全文

• 作者：Hamed Moradkhani ; Mir-Shahabeddin Izadkhah…
• 关键词：Experimental ; CFD ; PBM ; Oxygen mass transfer coefficient ; Impellers ; Aeration
• 刊名：Applied Biochemistry and Biotechnology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：181
• 期：2
• 页码：710-724
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Biotechnology; Biochemistry, general;
• 出版者：Springer US
• ISSN：1559-0291
• 卷排序：181

文摘

In this work, gas dispersion in a two-phase partitioning bioreactor is analyzed by calculating volumetric oxygen mass transfer coefficient which is modeled using a commercial computational fluid dynamics (CFD), code FLUENT 6.2. Dispersed oxygen bubbles dynamics is based on standard “k-ε” Reynolds-averaged Navier-Stokes (RANS) model. This paper describes a three-dimensional CFD model coupled with population balance equations (PBE) in order to get more confirming results of experimental measurements. Values of k_La are obtained using dynamic gassing-out method. Using the CFD simulation, the volumetric mass transfer coefficient is calculated based on Higbie’s penetration theory. Characteristics of mass transfer coefficient are investigated for five configurations of impeller and three different aeration flow rates. The pitched six blade type, due to the creation of downward flow direction, leads to higher dissolved oxygen (DO) concentrations, thereby, higher values of k_La compared with other impeller compositions. The magnitude of dissolved oxygen percentage in the aqueous phase has direct correlation with impeller speed and any increase of the aeration magnitude leads to faster saturation in shorter periods of time. Agitation speeds of 300 to 800 rpm are found to be the most effective rotational speeds for the mass transfer of oxygen in two-phase partitioning bioreactors (TPPB).