Comparative Performance Indexes for Ethanol Production Based on Autonomous and Annexed Sugarcane Plants

Future biomass conversion systems have to be developed using advanced technological routes in order to compete with fossil fuels, as well as to fulfill sustainability criteria. An attractive biomass feedstock for ethanol production is sugarcane, which is available in large amounts in several regions around the world. Although first-generation ethanol is a consolidated process, due to their large-scale production and tradition, there is still room for improved economic and environmental outcomes in the bioethanol industry.Bearing this in mind, this work presents a detailed process design strategy for biomass to ethanol production (1st-generation ethanol technology) from sugarcane. The simulation processes were performed using Aspen Plus® software focus on the annexed plant (production of bioethanol and sugar) and autonomous distillery(only bioethanol is produced) systems. Furthermore, a performance comparison in terms of the exergy efficiency and the destroyed exergy rate as a metric conversion of the processes are determined. Hence, the techno-economic bottlenecks in bioethanol production are attained using the exergy as an index. In addition, the sustainability aspects involved in the process design of the sugarcane biorefineries was discussed through the renewability exergy index. The results showed that the annexed plant has a reduction in the process irreversibilities rate of 6 % approximately, and in the average unitary exergy cost rate of 10 % approximately, in comparison to the autonomous distillery. Even though the proposed methodology is applied to 1G ethanol, it may well suited for several bioprocesses as a tool to help in taking decisions regarding design as well as operational policy definitions.