Dynamic Process Intensification via Data-Driven Dynamic Optimization: Concept and Application to Ternary Distillation

• Published in: Industrial & engineering chemistry research Vol. 60; no. 28
• Main Authors: Yan, Lingqing, Deneke, Tewodros L., Heljanko, Keijo, Harjunkoski, Iiro, Edgar, Thomas F., Baldea, Michael
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society (ACS) 06.07.2021
• Subjects: distillation; energy; ENGINEERING; optimization; process intensification; quality management; separation science
• ISSN: 0888-5885; 1520-5045

Process intensification is a design philosophy aimed at making chemical processes safer and more efficient. Its implementation often results in significant modifications to the design and structure of the process, with several conventional unit operations occurring in the same physical device. Traditionally, process intensification has focused on steady-state operation. In our previous works, we introduced dynamic process intensification (DPI) as a new intensification paradigm based on operational changes for conventional or intensified units. DPI is predicated on switching operation between two auxiliary steady states selected via a steady-state optimization calculation that ensures that the system generates, on average and over time, the same products as in nominal steady-state operation, but with favorable economics. This paper extends the DPI concept and introduces a novel dynamic optimization-based DPI strategy (Do-DPI) that involves imposing a true cyclic operation rather than switching between two discrete states. We discuss its implementation using surrogate dynamic models learned via system identification. Here, an extensive case study concerning a ternary distillation column separating a canonical hydrocarbon mixture shows that Do-DPI can reduce energy use by more than 4% relative to steady-state operation, with no significant deviations in product quality and production rate.