A New Photobioreactor Design With Enhanced Light Utilization And Hydrodynamic Performance

Enhancing the performance of Photobioreactors for microalgae cultivation has been a focal point for researchers in recent years. Computational fluid dynamics, employed to simulate the behavior of Photobioreactors, stands out as one of the most promising methods. Utilizing computational fluid dynamic simulations lowers design costs and enhances overall work efficiency. This study undertakes a comparative analysis of hydrodynamic behavior and light penetration in two stirred photobioreactors. A cactus-like photobioreactor and a cylindrical photobioreactor were designed. A Computational Fluid Dynamic simulation was conducted on ANSYS FLUENT. The outcomes of the simulation using the volume of fluid turbulence model and the discrete ordinates radiation model revealed that the innovative photobioreactor boasts an improved vortex flow field, reduced dead zone formation, a more uniform and elevated radiation intensity within the reactor's walls, and a higher air volume fraction. In addition, two strains of microalgae (Ankistrodesmus sp. and Chlorella sp.) were cultivated inside the two photobioreactors, with a maximum biomass productivity of 0.0364 g.L<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>. d<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and 0.0142 g.L<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>. d<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> was observed in the cactus-like photobioreactor and the cylindrical photobioreactor respectively. The increase in biomass productivity could be linked to better mixing behavior, higher mass transfer due to better gas dispersion, and higher light penetration that promoted the photosynthesis of the microalgae and fostered their growth.