Developing an integrated mathematical model of fermentation-pervaporation system for bioethanol production

Abstract

This study presents a novel integrated model to describe the fermentation-pervaporation system for bioethanol recovery. The proposed model incorporates the effects of by-product inhibition on the fermentation process and variation in feed concentration during the pervaporation process. The model is based on a modified Monod model to describe the fermentation process and the solution diffusion model for the pervaporation process, which can predict the concentrations of biomass, glucose, and ethanol in the bioreactor, as well as the partial flux of ethanol and water, total flux, the volume of permeate, and concentration of ethanol permeate. Simulation results showed that the proposed modified Monod model outperforms the conventional Monod model in predicting biomass, glucose, and ethanol concentrations due to its ability to consider the inhibitory effect of by-products with low mean absolute prediction error values of 4.1%, 12.6 and 5.2%. Moreover, the inclusion of the byproduct inhibitory effect in the fermentation model improved the accuracy of the integrated model in predicting the bioethanol permeation flux by 7.9%. The proposed integrated model provides a useful tool for designing and optimizing fermentation-pervaporation systems for bioethanol recovery to promote the adoption of continuous fermentation at the industrial scale.