Rate-based modeling and optimization of a Butyl-lactate production process by reactive distillation

• A rigorous rate-based model of a reactive distillation process was optimized. • A custom Genetic Algorithm minimized the Total Annualized Cost by 2.67%. • The optimized design achieves a 70% reduction in reboiler energy consumption. • Hydraulic and thermal analyses confirmed the feasibility of the superior design. n-Butyl lactate is a promising green solvent whose production can be efficiently intensified using reactive distillation (RD). However, the optimal design of such a process is a complex challenge due to its highly non-linear nature and the interplay between reaction, separation, and economics. In this work, a rigorous rate-based model of an industrial-scale n-butyl lactate production process was developed and optimized. A custom Genetic Algorithm (GA) was implemented to solve the complex, mixed-integer optimization problem, with the objective of minimizing the Total Annualized Cost (TAC). The GA successfully converged to a superior design, achieving a TAC of 1679 USD/t, compared to a validated base case (1725 USD/t). The feasibility and superiority of the optimized design were confirmed through a comprehensive post-optimization analysis, leveraging the high fidelity of the rate-based model, which accounts for mass and heat transfer limitations. Detailed hydraulic, thermal (via Column Grand Composite Curves), and sustainability analyses demonstrated that the new design is not only more economical but also operationally stable and more energy-efficient (with an energy intensity reduction of 262 kJ/kg), while maintaining excellent mass efficiency. This study provides a holistic and validated framework for the design of an industrial process for n-butyl lactate production.