Conceptual design and optimal tuning of decentralized control loops for chemical plants: Application to the Tennessee-Eastman Process
Systematic methods and tools for managing the complexity
Tools Integration - CAPE Methods & Tools (T4-10)
Keywords: plant wide control optimal tuning plant stability
Conceptual design and optimal tuning of decentralized control loops for chemical plants: Application to the Tennessee-Eastman Process
Luis T. Antelo, Oliver Exler, Julio R. Banga, Antonio A. Alonso*
Process Engineering Group. IIM-CSIC. C/ Eduardo Cabello, 6,
36208, Vigo, Spain.
* Corresponding author
In this work we describe a conceptual approach which has been recently developed to design efficient decentralized control structures for chemical plants. The approach combines concepts from thermodynamics, inventory networks and process control as developed by Alonso et al (2002) and Antelo et al (2006) to construct a set of stable and robust decentralized control candidate structures. Such candidates consist of inventory control loops designed so to ensure convergence of the mass and energy inventories to given references and thus guaranteeing stability of the extensive properties despite plant disturbances or even parameter uncertainty. Note that since loops are defined over inventories, they contain almost every possible decentralized alternative. Finally, the structure of the control loops in each element of this set (namely each inventory control loop candidate) is then completed by providing a physical realization for the extensive and intensive variable control loops over the available degrees of freedom which usually reduces to the material flows available in the process.
Note that the set we construct in this way can be interpreted as a superstructure which turns out to contain only stable (and robust) decentralized control candidates. Therefore, it offers a well structured framework for the application of NLP or MINLP approaches to select optimal and robust alternatives based on economic of operational objectives.
In this contribution, the different aspects of the conceptual design approach will be illustrated on the well known Tennessee-Eastman Process. In particular the benchmark case will be employed to illustrate the definition of the stable inventory alternatives, physical realization and optimal selection and tuning by an efficient and recently developed MINLP solver.
References
Alonso, A. A., B. E. Ydstie and J. R. Banga (2002) From irreversible thermodynamics to a robust control theory for distributed process systems. J. Proc. Control. 12:507-517
Antelo, L.T. I Otero-Muras, J. R. Banga, A.A. Alonso (2006) A systematic approach to plant-wide control based on thermodynamics. Comp. Chem. Eng. In Press
Presented Thursday 20, 09:20 to 09:37, in session Tools Integration - CAPE Methods & Tools (T4-10).
