CFD modeling of CO₂ fixation by microalgae cultivated in a lab scale photobioreactor

The green microalga Chlorella vulgaris has been studied for efficient fixation of carbon dioxide, CO₂, from elevated concentrations of in-feed gas flows. In this work, a Computational Fluid Dynamics (CFD) model for algae cultivation including the dependence on CO₂ concentration in liquid has been derived based on cultivation experiments of Chlorella vulgaris. The experiments were performed in a laboratory scale cylindrical stirred tank reactor with a range of enriched CO₂ concentrations in-feed (0.04-50 %). The model provided by Béchet et al. (2015) for algae cultivation considering dependence on local light, algae concentration and temperature has been implemented for CFD and modified for comprising CO₂ dependence. The model has been verified with experimental results for the algae productivity showing the proper trends for dissolved CO₂ concentrations and algae concentrations. Thus, the developed CFD model can serve as a tool for evaluating photobioreactor performance for CO₂ capture.