Gradient-Based Extremum Seeking Control Applied to a Dark Fermentation Process

Abstract

In this paper we use an extremum seeking control strategy to maximize the produced ethanol in a dark fermenter. Such a strategy avails of a continuous estimation of the reactor’s input-output gradient to compute the dilution rate applied to the reactor. This dilution rate, however, is updated at discrete moments. We consider a scenario in which tequila vinasse is the raw material for this fermentation process; thereby reducing the concentrations of sugars in the vinasse and at the same time obtaining ethanol. Via numerical simulations we show the applicability of the strategy when the optimal concentration of ethanol varies in time as step functions.