Experimental characterization and numerical simulation of the hydrodynamics in an airlift photobioreactor for microalgae cultures

Abstract

The development of photobioreactors optimized to increase the biomass production from phototrophic microalgae cultures assumes a major concern for the economic viability of different processes (biofuel production, carbon dioxide mitigation, pigments …). The main aim of this study is to establish and validate a CFD hydrodynamic model for a flat panel airlift photobioreactor configuration. In this regard, experimental water flow rates induced in the riser of the reactor and the liquid circulation were compared to the CFD solution obtained thanks to the Fluent® software. The numerical simulation results were relevant. Subsequently, cultures of Scenedesmus obliquus (CCAP 276/3A) were achieved to determine an optimal injected air flow rate for our configuration of photobioreactor. This air flow rate was 1.5L·min−1. Measurement of the mass transfer coefficient (kLa) of carbon dioxide in the culture medium was 3.10−4s−1 and the mixing time for this optimal operating condition is 312s.