Towards White-box Environmental and Economic Process Optimization: Tailoring Modelling Approaches to Multi-scale Simulations.

Systems and Control Transactions, vol. 6, pp. 1189–1196

Abstract

Polylactic acid (PLA) is the most produced bioplastic, however, for it to compete with fossil-based plastics, maximum production efficiency is crucial. To achieve this, all scales, from catalyst scale to process scale, must be simultaneously considered. This challenge is particularly relevant for PLA production, where complex interactions of multiple phenomena occur in several unit operations and the development of active non-toxic catalysts is of major importance. For these reasons, developing a framework that allows a comprehensive understanding of the influence of design choices at different levels is of paramount importance. To address this, a multi-scale model was developed for the PLA production, coupling a custom devolatilizer reactor model to a process simulator that is subsequently linked to an environmental assessment tool via Python-based interfaces. With this model, sensitivity analysis was performed to assess the influence of operational variables on the most relevant KPI’s. Results showed that changes of only 5.5 torr in the devolatilizer pressure can lead to total utility consumption and climate change impact variations of 13% and 2%, respectively. This demonstrates the critical role of the devolatilizers in the process, highlighting the importance of developing custom unit operation models coupled to the process simulator. Additionally, the results show that, with this framework, the influence of reactor scale variables on industrial environmental performance can be seamlessly assessed. Overall, this work demonstrates the feasibility and value of integrated multi-scale modeling for sustainable process design and provides a solid foundation for the future development of a multi-scale environmental and economic optimization framework.

Authors 3

1. Thomas Hietala

   University of Lisbon · Instituto Superior Técnico · Centro de Química Estrutural

   Affiliation as printed

   Centro de Química Estrutural - IMS, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal

2. Sonja Herres‐Pawlis Aachen Institute of Inorganic Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Inorganic Chemistry, RWTH Aachen University, Aachen, Germany

3. Pedro S.F. Mendes

   University of Lisbon · Instituto Superior Técnico · Centro de Química Estrutural

   Affiliation as printed

   Centro de Química Estrutural - IMS, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal