Abstract
The urgent need for sustainable and renewable energy has positioned bioethanol as a promising alternative to fossil fuels due to its biodegradability, reduced carbon footprint, and potential to utilize lignocellulosic biomass, yet conventional production processes remain highly energy- and water-intensive, threatening economic feasibility and environmental sustainability. This study presents a hybrid optimization methodology that integrates Pinch Analysis and Mixed Integer Linear Programming (MILP) to systematically enhance heat and water recovery in a lignocellulosic bioethanol plant. Pinch Analysis was first applied to identify thermodynamic efficiency targets, revealing potential energy savings of up to 38 % through strategic heat exchanger network design and water reuse opportunities, after which a MILP model was developed to determine cost-optimal hot–cold stream matches, exchanger placements, and water reuse configurations, ensuring feasibility while minimizing utility consumption and capital expenditures. Results demonstrated that the hybrid approach reduced hot and cold utility requirements by more than 40 % compared to baseline operations, while freshwater intake and wastewater discharge were lowered by approximately 30–35 %. Furthermore, integration of Life Cycle Assessment (LCA) confirmed that the optimized process achieved a 28 % reduction in greenhouse gas emissions, a 22 % decrease in cumulative energy demand, and a 30 % improvement in water footprint, with additional reductions in acidification and eutrophication impacts, thereby validating the environmental benefits of the optimization framework. Overall, the combined thermodynamic and mathematical programming approach provides not only technical efficiency but also long-term economic and ecological viability, demonstrating that hybrid Pinch–MILP optimization, validated through LCA, offers a robust, scalable framework for advancing sustainable bioethanol production. By bridging process integration, optimization, and environmental assessment, this study contributes to the transition toward renewable, resource-efficient energy systems and establishes practical strategies for industry-wide implementation.
