Diurnal and nocturnal pH control in microalgae raceway reactors by combining classical and event-based control approaches

Abstract

The pH control in raceway reactors is crucial for an optimal performance of the system. Classical pH control is exclusively performed during the day-time period for cost saving reasons. This paper demonstrates that pH can be controlled 24 hours a day by using both a continuous-based and an event-based control approaches, being able to improve the system’s performance reducing costs at the same time. Thus, experimental tests on a raceway reactor for several days are presented to show a comparison between traditional control algorithms during the daytime period versus an event-based control approach operating during both daytime and nighttime periods. As a result, the combination of classical PI control for the daytime period and the event-based control for the nighttime period is presented as a promising pH control architecture in raceway reactors.