Analysis of Control Properties as a Sustainability Indicator in Intensified Processes for Levulinic Acid Purification

The evaluation of control properties in industrial processes is essential to achieve sustainability, a very relevant topic today. This study emphasizes the importance of control studies to ensure that processes are efficient, operable and safe. While strategies such as process intensification can reduce the size, cost, and consumption of energy, it can present challenges in control and operability. This work focuses on the evaluation of the control properties of schemes with different degrees of intensification for the purification of levulinic acid, with the aim of identifying designs with the best control properties and the best economic and environmental indicators. The schemes were designed under a systematic synthesis strategy and optimized using the hybrid method of differential evolution with a tabu list, considering the total annual cost and Eco-indicator 99. An open-loop study analyzed the relationship between manipulable variables and output variables using total condition number, sensitivity index, and relative gain matrix analysis. The dynamic behavior in a closed loop was subsequently analyzed using the minimization of the absolute error integral as a criterion. The results showed that the design, which includes a liquid-liquid extraction column, three distillation columns, and thermal coupling, presented the best dynamic performance. This design had a low total condition number, a below-average sensitivity index, a stable control structure, and low values of the absolute error integral. In addition, it stood out for its excellent cost and environmental impact indicators, which makes it the most favorable option among the proposed designs.