A pseudo‐transient optimization framework for periodic processes: Pressure swing adsorption and simulated moving bed chromatography. Issue 8 (2nd November 2017)

• Record Type: Journal Article
• Authors: Tsay, Calvin; Pattison, Richard C.; Baldea, Michael
• Is Part Of: AIChE journal. Volume 64:Issue 8(2018)
• Page Start: 2982
• Page End: 2996
• Publication Date: 2017-11-02
• Subjects: pressure‐swing adsorption -- chromatography -- periodic processes -- dynamic optimization -- pseudo‐transient simulation; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; 660.28
• DOI: 10.1002/aic.15987
• Languages: English
• ISSNs: 0001-1541

Abstract

Abstract : Periodic systems are widely used in separation processes and in reaction engineering. They are designed for and operated at a cyclic steady state (CSS). Identifying and optimizing the CSS has proven to be computationally challenging. A novel framework for equation‐oriented simulation and optimization of cyclic processes is introduced. A two‐step reformulation of the process model is proposed, comprising, (1) a full discretization of the time and spatial domains and (2) recasting the discretized model as a differential‐algebraic equation system, for which theoretical stability guarantees are provided. Additionally, a mathematical, structural connection between the CSS constraints and material recycling is established, which allows us to deal with these conditions via a "tearing" procedure. These developments are integrated in a pseudo‐transient design optimization framework and two extensive case studies are presented: a simulated moving bed chromatography system and a pressure swing adsorption process. © 2017 American Institute of Chemical Engineers AIChE J, 64: 2982–2996, 2018