A process design framework for considering the stability of steady state operating points and Hopf singularity points in chemical processes

A review from 1996 to 2021 of tuning methodologies and controller structures applied for an unstable/stable (bio)reactor with imperfect mixing and bypass

This paper presents a critical review of tuning methodologies and controller structures applied to the Cholette bioreactor. This (bio)reactor has been studied extensively by the automatic control community from the point of view of controller structures and tuning methodologies, from controllers with a single structure to nonlinear controllers, and from the synthesis method to the frequency response. Therefore, new trends and opportunities of study have been detected with regard to their operating points, controller structures and tuning methodologies which could be addressed for this system.

Analysis of open-loop and L2∕D controlled closed-loop behavior of the Cholette's bioreactor under different operating conditions

The scope of this paper is the analysis of open-loop and L₂/D controlled closed-loop behavior of the Cholette's bioreactor under different operating conditions. The open-loop behavior is studied by means of the steady-state multiplicity areas formed by substrate feed concentration and substrate concentration in the output using the nonlinear model of the bioreactor. The stability of each steady-state inside areas is determined by a polynomial representation. The nonlinear dynamic and steady-state multiplicity areas of the Cholette's bioreactor are shown to depend on the operating conditions and concentration required. The closed-loop behavior is studied by the tuning of a set of Pareto-optimal L₂/D linear controllers at a stable operating point. Numerical simulations and phase portraits are used to evaluate the control system. This paper could be a guide for theoretical and practical applications in the fields of biotechnology and automatic control.