Effective utilization of flue gases in raceway reactor with event-based pH control for microalgae culture

•The algorithm allows to reduce the amount of flue gases injected into raceway reactor.•The pH control accuracy is improved what has a direct influence on biomass production.•Only necessary amount of CO2 is supplied keeping the pH close to its optimal value. This work addresses effective utilization of flue gases through the proper pH control in raceway reactors. The pH control problem has been addressed with an event-based control approach using a Generalized Predictive Controller (GPC) with actuator deadband. Applying this control strategy it is possible to reduce the control effort, and at the same time saving control resources. In the pH process case, the event-based controller with actuator deadband can be tuned to supply only necessary amount of CO2 to keep the pH close to its optimal value. On the other hand, the evaluated control algorithm significantly improves the pH control accuracy, what has a direct influence on biomass production. In order to test the performance of the event-based GPC controller, several experiments have been performed on a real raceway reactor. Additionally, several control performance indexes have been used to compare the analyzed technique with commonly used on/off controller.