Thursday, April 22, 2010 - 1:30 PM
12-02

Control of a fermentation process to produce biobutanol

Adriano Pinto Mariano1, Caliane B. B. Costa1, Dejanira F. Angelis2, Daniel Ibraim Pires Atala3, Francisco Maugeri3, Maria Regina Wolf Maciel1, and Rubens Maciel Filho1. (1) Department of Chemical Process, State University of Campinas (UNICAMP) - School of Chemical Engineering, CP 6066, ZIP CODE 13083-970, Campinas-SP, Brazil, (2) Department of Biochemistry and Microbiology - Institute of Biosciences, São Paulo State University, UNESP, Rio Claro, Brazil, (3) School of Food Engineering, University of Campinas, UNICAMP, Monteiro Lobato Street, 80, Campinas, 13081970, Brazil

The industrial implementation of a process to produce biobutanol will demand a control strategy robust enough to deal with common fluctuations in the quality of the agricultural raw material. For example, in the ethanol fermentation, one of the sources of raw material quality fluctuations is the alteration in the amounts of treated sugar-cane juice and molasses used in the composition of the medium fed to the fermentor. These alterations are made due to the sugar factories operation. Furthermore, molasses undergoes variation of composition in different crops. Consequently, the control must be designed in order to keep the substrate conversion at a desired value, and to avoid variations in butanol concentration in the fermentor.

In this work control strategies for a process designed to produce biobutanol were studied. The process represented by a mathematical model consists of three interconnected units, as follows: fermentor, cell retention system (tangential microfiltration) and vacuum flash vessel (responsible for the continuous recovery of butanol from the broth). Based on the study of the dynamics of the process, suitable feedback control strategies were elaborated to deal with disturbances related to fluctuation of the sugar concentration in the raw material. The regulatory control consisted in keeping sugar and/or butanol concentrations in the fermentor constant in face of the disturbances. The performance of the classical proportional-integral controller (PI) was evaluated. The controller was able to regulate the operating conditions in order to accommodate the perturbations with the lowest possible alterations in the process outputs.



Web Page: DOI: 10.1007/s12010-009-8754-1

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