Sequential Synthesis Methodology in the Design and Optimization of Sustainable Distillation Sequences for Levulinic Acid Purification

Abstract

Abstract The biorefinery concept has been considered the most effective and sustainable method for transforming biomass into valuable products. Levulinic acid, derived from the acid hydrolysis of glucose in lignocellulosic biomass, is acknowledged as a valuable and versatile high-value product. The separation and purification of levulinic acid become complicated due to azeotropic characteristics and excess water in the resulting dilute mixture from acid hydrolysis. This complexity makes the process energy-intensive and costly, posing challenges for large-scale production. For this reason, it has been the subject of research proposing separation methods, such as the use of liquid-liquid extraction columns, decanters, and intensified columns. However, a comprehensive and sustainable systematic synthesis has not yet been undertaken to identify the most cost-effective and environmentally friendly design. In this research, several potential process designs for the purification of levulinic acid were analyzed and compared. These designs were developed using a sequential synthesis methodology, designed, and optimized through a rigorous optimization process employing a multi-objective hybrid algorithm, specifically, differential evolution with tabu list. Two objectives were considered: total annual cost as the economic criterion, and the eco-indicator 99 as the environmental index. The results indicated that the intensified design, incorporating a thermal coupling demonstrated superior results, with cost savings of approximately 25% and a 21% reduction in environmental impact. Therefore, the sequential synthesis produced alternatives for levulinic acid purification that align with the United Nations' 2030 Agenda Sustainable Development Goals, contributing to the creation of sustainable processes.