Model-based versus model-free control designs for improving microalgae growth in a closed photobioreactor: Some preliminary comparisons

Controlling microalgae cultivation, i.e., a crucial industrial topic today, is a challenging task since the corresponding modeling is complex, highly uncertain and time-varying. A model-free control setting is therefore introduced in order to ensure a high growth of microalgae in a continuous closed photobioreactor. Computer simulations are displayed in order to compare this design to an input-output feedback linearizing control strategy, which is widely used in the academic literature on photobioreactors. They assess the superiority of the model-free standpoint both in terms of performances and implementation simplicity.Comment: The 24th Mediterranean Conference on Control and Automation (MED'16), Athens, Greece (June 21-24, 2016

Oxygen Control for an Industrial Pilot-Scale Fed-Batch Filamentous Fungal Fermentation

Industrial filamentous fungal fermentations are typically operated in fed- batch mode. Oxygen control represents an important operational challenge due to the varying biomass concentration. In this study, oxygen control is implemented by manipulating the substrate feed rate, i.e. the rate of oxygen consumption. It turns out that the setpoint for dissolved oxygen represents a trade-off since a low dissolved oxygen value favors productivity but can also induce oxygen limitation. This paper addresses the regulation of dissolved oxygen using a cascade control scheme that incorporates auxiliary measurements to improve the control performance. The computation of an appropriate setpoint profile for dissolved oxygen is solved via process optimization. For that purpose, an existing morphologically structured model is extended to include the effects of both low levels of oxygen on growth and medium rheological properties on oxygen transfer. Experimental results obtained at the industrial pilot-scale level confirm the efficiency of the proposed control strategy but also illustrate the shortcomings of the process model at hand for optimizing the dissolved oxygen setpoints

CONTROLE DU PROFIL AROMATIQUE DE LA BIERE LORS DE LA FERMENTATION ALCOOLIQUE

GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Predictive control of the light-to-microalgae ratio for Chlamydomonas reinhardtii in a photobioreactor

International audienc

Real-Time optimization of fed-batch bioreactors via adaptive extremum-seeking control

This paper is concerned with the real-time optimization of fed-batch bioreactors with Haldane kinetics. The proposed adaptive extremum seeking approach utilizes the structure information of the process kinetics to derive a seeking algorithm that drives the system states to the desired set-points that maximize the biomass production. Lyapunov's stability theorem is used in the design of the extremum seeking controller structure and the development of the parameter learning laws. The performance of the approach is illustrated via numerical simulations

Adaptive Extremum Seeking Control of Enzyme Production in Filamentous Fungal Fermentation

The aim of this paper is to investigate, via a case study, an adaptive extremum seeking control scheme for product formation in fed-batch bioreactors. The presented approach utilizes the structure information of the Haldane kinetic model, to derive an extremum seeking algorithm that drives the system to the desired set points with the objective to maximize the product formation rate. The adaptive extremum seeking algorithm consists of a control law and parameter learning laws designed by using Lyapunov’s stability arguments. The adaptive extremum seeking control scheme is applied to the maximization of the enzyme production yield in filamentous fungal fermentation. Numerical simulations are provided in order to investigate the effectiveness of the proposed scheme

Online estimation of microalgae growth in photobioreactor based on oxygen in situ measurements

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A hybrid asymptotic-Kalman observer for estimation of microalgae growth in a closed photobioreactor

International audienceMicroalgae are widely studied as a promising solution for the challenges raised by the sustainable development. Monitoring these kind of cultures is a hard task due to the cost of the physical sensors and the lack of reliable ones for some biochemical variables, especially for the online measurement of biomass concentration. This paper proposes an observer for the biomass concentration based on the online measurement of the dissolved oxygen in the culture. An Hybrid Observer is developed, by the combination of a Kalman filter and an asymptotic observer. The performance and tuning of the Hybrid observer is discussed and highlighted in simulation in the case of a continuous culture of the microalgae C. reinhardtii, performed in a closed photobioreactor