Techno-economic feasibility and exergy analysis of bioethanol production from waste
Annlyn Mary Joseph, Yeswanth Tulasi, Devashish Shrivastava, Bandaru Kiran
Abstract
The increased dependence on fossil fuels has led to its shortage. Adding to this, awareness around the world has risen about the ill effects of fossil fuels and thus there has been an increasing shift to green sources of fuel. At the production level, ethanol has a significant effect on agricultural commodity markets, and with the price of the commodities approximately doubling in the past few years, feedstock prices have increased significantly. Bioethanol obtained from non-food sources can also eliminate the dependence on oil. In this work, two models are developed using Aspen Plus V11 for the production of bioethanol using second-generation feedstocks (waste materials) i.e., sugarcane bagasse and brown algae. The basic process involves four main steps which are the Pretreatment of the raw materials, the saccharification, the fermentation process of the pre-treated product using the necessary enzymes, and the purification process. A detailed exergy analysis for the processes was carried out which showed that for 2000 tons per day of feed used in the processes, the exergy losses were around 625 kW and 180 kW for sugar cane bagasse and brown algae as feedstocks respectively. An economic analysis was performed using the Aspen economic analyzer which estimated the Total capital investment per gallon of bioethanol at around USD 17 and USD 12 for the production processes of bioethanol using sugar cane bagasse and brown algae respectively.