Modelling light transmission, cyanobacterial growth kinetics and fluid dynamics in a laboratory scale multiphase photo-bioreactor for biological hydrogen production

An integrated reactor model was designed in this research to simulate fluid dynamics, local light intensity and the growth rate of nitrogen-fixing cyanobacterium Cyanothece sp. ATCC 51142 in a flat-plate photo-bioreactor by CFD technique. Previous research had already given the parameters in different algal growth kinetic equations. In this research, parameters were modified by CFD technique to improve the accuracy of cyanobacterial growth kinetic models. Finally, effects of recycling gas flow rate and geometry of sparger on local light intensity, growth rate, and fluid dynamics were analysed. Results show that recycling gas flow can increase liquid velocity and bubble volume fraction, however it prevents light transmission and the growth of cyanobacterium. Geometry of the sparger can affect liquid movement and distribution of both local light intensity and local growth rate.