MODELING ETHANOL AND SECONDARY INHIBITIONS OF ETHANOL FERMENTATION IN A MULTISTAGE REACTOR

A kinetic model of ethanol fermentation conducted under a variety of conditions in a continuous four-stage reactor is proposed. The expressions for specific growth and product formation rates are: .mu. = .mu.0 exp(- k1P)(1 - X/X2); .nu.p = .nu.0 exp(- k2P)(1 - X/X2). Parameters were identified by nonlinear programming and shown to fit data correctly for steady states of seven different experiments. The product inhibition constants were of 27 and 84 g/L, respectively. Secondary inhibitions were represented by the linear biomass term. The proposed model gave a better description of phenomena than one which only took ethanol inhibition into account. The same model also fitted batch fermentation data, with only some parameters altering significantly. The use of this model for on-line purposes is discussed.