Dissolved oxygen control in raceway reactors based on mass transfer demand.

Improvement of mass transfer capacity and reduction of production costs.

Experimental tests demonstrate the capabilities of the proposed methodology.

Raceway reactors are still the most extensive technology for microalgae production. However, these reactors have some drawbacks, one of them being a low mass transfer capacity, which provokes dissolved oxygen accumulation and thus reduction of system performance. To overcome this problem, it is imperative to improve the photobioreactor design as well as the operating conditions. One solution is to maintain the dissolved oxygen below defined limits. In this work, a new control algorithm is proposed to improve the mass transfer capacity of raceway reactors while at the same time reducing air injection costs. The main idea of the proposed control approach is that only the necessary amount of airflow will be applied according to transfer capacity demand. This control strategy was first analyzed in simulation and compared with classical On/Off solutions, and subsequently evaluated in outdoor conditions in a photobioreactor of 80 m2.

Supervisory Control And Data Acquisition

Simple Internal Model Control

Microalgae

Raceway

Oxygen accumulation

Process control

Transfer capacity

Gas injection efficiency

© 2022 The Author(s). Published by Elsevier B.V.