Modeling and simulation of an integrated bioethanol-hydrogen production process

Hydrogen (H2) production from renewable feedstocks such as bioethanol represents one of the sustainable and environmentally benign methods of making the proposed utilization of H2 as energy carrier of the future a reality. However, successful implementation of this technology depends on several factors which include understanding of the technicality, as well as process design and modelling. Generally, this area of research has not received adequate attentions. In this article, an integrated process for producing H2 through starch hydrolysis, fermentation, and ethanol steam reforming (ESTR) process has been proposed. Enzymatic hydrolysis of starch was performed to obtain the fermentable sugar (hydrolysate). In addition, batch fermentation experiments were carried out using a laboratory scale fermenter with yeast (Saccharomyces cerevisiae) culture adapted for anaerobic conversion of the hydrolysate to bioethanol. Subsequently, kinetic data obtained from these experiments was employed to guide thermodynamic modeling of fermentation process which was coupled with the ESTR model and was implemented in the Aspen HYSYS simulator. The results ultimately revealed pertinent information which could find applications in the implementation of the proposed integrated process for bioethanol and H2 production.