TITLE:
Enhanced Mass Transfer in Microbubble Driven Airlift Bioreactor for Microalgal Culture
AUTHORS:
Kezhen Ying, Mahmood K. H. Al-Mashhadani, James O. Hanotu, Daniel J. Gilmour, William B. Zimmerman
KEYWORDS:
Microbubbles; KLa; CO2 Capture; Algal Culture
JOURNAL NAME:
Engineering,
Vol.5 No.9,
August
29,
2013
ABSTRACT: In this study, the effect of microfluidic
microbubbles on overall gas-liquid mass transfer (CO2 dissolution
and O2 removal) was investigated under five different flow rates. The
effect of different liquid substrate on CO2 mass transfer properties
was also tested. The results showed that the KLa can be enhanced by either increasing the dosing
flowrate or reducing the bubble size; however, increasing the flow rate to
achieve a higher KLa would
ultimately lower the CO2 capture efficiency. In order to achieve
both higher CO2 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% CO2 gas showed
improved KLa 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 KLa, divided by the pH of
8.4.