Authors: Samriddha Sharma, Om Prakash Sondhiya
Abstract: The increasing environmental and economic concerns associated with fossil-fuel dependency have intensified global interest in renewable transportation fuels. Among alternative biofuels, bioethanol has emerged as one of the most commercially viable and widely adopted options because it can be produced from renewable biomass resources and integrated into existing fuel infrastructures. This study presents a comparative process-design assessment of a compact bioethanol production system utilizing three abundant lignocellulosic agricultural residues: rice straw, sugarcane bagasse, and corn stover. A literature-informed process model was developed for a small-scale educational bioethanol unit comprising feedstock preparation, dilute-acid pretreatment, enzymatic hydrolysis, yeast fermentation, and reflux-assisted distillation. The investigation evaluates the influence of biomass composition on fermentable sugar recovery, ethanol yield, process efficiency, and energy demand. The modeled analysis indicates that sugarcane bagasse demonstrates the most favorable conversion performance under the selected operating assumptions, yielding approximately 74 g/L fermentable sugars and 34.5 g/L ethanol prior to separation. Corn stover exhibited intermediate performance, whereas rice straw produced comparatively lower ethanol concentrations because of its elevated ash and silica content, which reduce carbohydrate accessibility during pretreatment. The results further reveal that pretreatment and distillation account for the majority of the process energy requirement, highlighting the importance of heat integration, solids management, and process optimization in improving system efficiency. The study concludes that a modular small-scale bioethanol system can serve as an effective educational and research platform for demonstrating biomass-to-fuel conversion technologies. Furthermore, transparent presentation of modeled assumptions and calculation procedures strengthens the academic reliability of design-stage biofuel studies intended for instructional and comparative analysis.
