Strategies for the Analysis of Continuous Bioethanol Fermentation under Periodical Forcing

Abstract

The process of continuous bioethanol fermentation often exhibits strong nonlinear dynamics and tends to generate self-oscillatory-state trajectories. The aim of this work is to further investigate such oscillators by coupling with outside periodic forcing, so as to improve process performance. To that end, several strategies for analyzing periodically forced self-oscillatory processes are proposed. By periodically and deliberately forcing an operational parameter, the behavior of the forced fermentor is investigated using limit cycle bifurcation analysis. Specifically, periodic doubling and Neimark–Sacker bifurcations are investigated with limit cycle continuation diagrams. The limit cycle bifurcation analysis is compared with the simulation-based methods, such as stroboscopic and maximum bifurcation maps, and it is shown to be an efficient analysis tool for the periodically forced self-oscillatory system. Process performance enhancement by designing the fermentor to be self-oscillatory is also discussed,...