Hybrid cybernetic model-based simulation of continuous production of lignocellulosic ethanol: Rejecting abruptly changing feed conditions

Abstract

Fermenting various sugars derived from lignocellulosic biomass promises to be attractive for producing ethanol, an important alternative fuel. Diversity of lignocellulosic biomass sources and pre-processing variations mean entering sugars are expected to experience large, though infrequent, changes. Recent developments in hybrid cybernetic modeling allow efficient in silica studies. This enables studying sequential linearization-based model predictive control for ensuring high productivity and conversion, for a chemostat seeded with yeast capable of co-fermentation. An appropriate controlled variable (conversion) and control formulation are ascertained. Also, a recently proposed hidden-Markov disturbance model, capable of describing the aforesaid changes, results in closed-loop performance superior to the typical integrated white-noise assumption. (C) 2009 Elsevier Ltd. All rights reserved.