Studies in the synthesis of control structures for chemical processes: Part I: Formulation of the problem. Process decomposition and the classification of the control tasks. Analysis of the optimizing control structures

Authors

  • Manfred Morari,

    Corresponding author
    1. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minn. 55455
    • Department of Chemical Engineering, University of Wisconsin, Madison, Wisconsin, 53706
    Search for more papers by this author
  • Yaman Arkun,

    1. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minn. 55455
    Current affiliation:
    1. Department of Chemical Engineering, Rensselaer Polytechnic Institute, Troy, New York, 12181
    Search for more papers by this author
  • George Stephanopoulos

    1. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minn. 55455
    Search for more papers by this author

Abstract

Part I of this series presents a unified formulation of the problem of synthesizing control structures for chemical processes. The formulation is rigorous and free of engineering heuristics, providing the framework for generalizations and further analytical developments on this important problem.

Decomposition is the underlying, guiding principle, leading to the classification of the control objectives (regulation, optimization) and the partitioning of the process for the practical implementation of the control structures. Within the framework of hierarchical control and multi-level optimization theory, mathematical measures have been developed to guide the decomposition of the control tasks and the partitioning of the process. Consequently, the extent and the purpose of the regulatory and optimizing control objectives for a given plant are well defined, and alternative control structures can be generated for the designer's analysis and screening.

In addition, in this first part we examine the features of various optimizing control strategies (feedforward, feedback; centralized, decentralized) and develop methods for their generation and selective screening. Application of all these principles is illustrated on an integrated chemical plant that offers enough variety and complexity to allow conclusions about a real-life situation.

Ancillary