Dynamic simulation of control systems for bioethanol reactive dehydration: Conventional and intensified case studies

Abstract

Bioethanol is produced through fermentation processes at very low concentrations. In order to be used as fuel in gasoline mixtures, it is necessary to have a purity of at least 99 wt.%. Both, separation and purification processes used are highly energy demanding, due to the presence of the azeotrope in the bioethanol - water mixture. A novel proposal is reactive dehydration with epoxides; however, without control the operation of the process cannot be guaranteed. Given this fact, this research presents, via dynamic simulation in Aspen Dynamics ® V8.8, the control systems for four reactive dehydration processes of bioethanol with ethylene oxide and propylene oxide, which support the operation of those technologies. It was found that it is possible to control the purity of bioethanol in reactive distillation by using temperature measures instead of compositions, thus reducing the dead times and allowing the control to be realizable.