Zhao S., Ding Y.-D., Zhu X., Liao Q., Huang Y., Fu Q., 2015, Impact of Microalgae on CO2 Bubble Growth and Detachment in Bubble Column Bioreactor, Chemical Engineering Transactions, 45, 1933-1938.
The biological capture of carbon dioxide (CO2) using microalgae is a promising technology and has gained a huge momentum due to its environment-friendly, low cost and high CO2 fixation efficiency. In the applications CO2 gas usually was pumped into photobioreactors in bubble form. The bubbles behavior significantly affects the mass transfer and distribution of the microalgae. Also the adhesion of microalgae and absorption of CO2 at the gas-liquid interface will certainly have an important effect on the dynamics of CO2 bubbles in bubble column bioreactor. In this work, visual experiments were conducted for studying the impacts of microalgae on CO2 bubble growth and detachment in bubble column bioreactor. It was found that many microalgae cells adsorbed on the surface of the bubble resulting in easier detachment of bubble in microalgae suspension against with pure water. Besides, it was also found that smaller capillary radius and larger CO2 concentration gave rise to decreasing bubble growth rate and detachment diameter which was conducive to CO2 transportation. Moreover, a critical gas flow velocity of 1.7 m/s in capillary was achieved, which divided the bubble growth status into steady and unsteady state, and different bubble growth and detachment behaviors were observed. These findings will be beneficial for the design of aeration system of photobioreactors for microalgae cultivation to enhance the mass transport at the interface.
