Enhanced Mass Transfer in Microbubble Driven Airlift Bioreactor for Microalgal Culture
- 1 Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
- 2 Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
- 3 Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
- 4 Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
- 5 Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
Abstract
In this study, the effect of microfluidic microbubbles on overall gas-liquid mass transfer (CO 2 dissolution and O 2 removal) was investigated under five different flow rates. The effect of different liquid substrate on CO 2 mass transfer properties was also tested. The results showed that the K L a can be enhanced by either increasing the dosing flowrate or reducing the bubble size; however, increasing the flow rate to achieve a higher K L a would ultimately lower the CO 2 capture efficiency. In order to achieve both higher CO 2 mass transfer rate and capture efficiency, reducing bubble size (e.g. using microbubbles) has been proved more promising than increasing flow rate. Microbubble dosing with 5% CO 2 gas showed improved K L a by 30% - 100% across different flow rates, compared to fine-bubble dosing. In the real algal culture medium, there appears to be two distinct stages in terms of K L a , divided by the pH of 8.4.
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