Effect of decision variables on algae growth in flat panel reactors

Biodiesel production using algae is a hot topic nowadays. To fulfill the future request for biodiesel produced with algae large-scale production facilities are necessary. The economical viability of these large-scale plants depends on a large number of decision variables. These decision variables concern both aspects of the design of the algae plant and the degree of integration of the algae plant with other processes, up and downstream. The goal of the first part of the study was to develop a model of a flat panel photobioreactor (PBR) and to use this model to investigate the effect of decision variables on biomass production. From literature knowledge on algal biomass production in a flat panel PBR was collected, combined and used as the basis of the model. The following decision variables were included in the model: location, reactor orientation, reactor dimensions, light path, biomass concentration, cultivation temperature, etc. For sunlight conditions measured sunlight intensities from meteorological institutes were used. With this model biomass production on a daily and yearly basis can be predicted. In addition, the model allows the studying of the effect of the decision variables on biomass production. Figure 1 gives an example of the predicted productivity of algae growth for four days in the Netherlands and in France. The figure shows that the differences in growth are not as high as being expected from the climatological differences between the countries. By systematic variation of the decision variables the algae cultivation system can be optimized for any global location.