An algorithm for gradient-based dynamic optimization of UV flash processes

Tobias Kasper Skovborg Ritschel, Andrea Capolei, Jozsef Gaspar, John Bagterp Jørgensen

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

This paper presents a novel single-shooting algorithm for gradient-based solution of optimal control problems with vapor-liquid equilibrium constraints. Such optimal control problems are important in several engineering applications, for instance in control of distillation columns, in certain two-phase flow problems, and in operation of oil reservoirs. The single-shooting algorithm uses an adjoint method for the computation of gradients. Furthermore, the algorithm uses either a simultaneous or a nested approach for the numerical solution of the dynamic vapor-liquid equilibrium model equations. Two numerical examples illustrate that the simultaneous approach is faster than the nested approach and that the efficiency of the underlying thermodynamic computations is important for the overall performance of the single-shooting algorithm. We compare the performance of different optimization softwareaswellastheperformanceofdifferentcompilersinaLinuxoperatingsystem. Thesetestsindicatethatreal-timenonlinear model predictive control of UV flash processes is computationally feasible.
Original languageEnglish
JournalComputers & Chemical Engineering
Volume114
Pages (from-to)281–295
ISSN0098-1354
DOIs
Publication statusPublished - 2018

Keywords

  • Dynamic optimization
  • Optimal control
  • Adjoint algorithm
  • Single-shooting
  • UV flash
  • Vapor–liquid equilibrium

Cite this

Ritschel, Tobias Kasper Skovborg ; Capolei, Andrea ; Gaspar, Jozsef ; Jørgensen, John Bagterp. / An algorithm for gradient-based dynamic optimization of UV flash processes. In: Computers & Chemical Engineering. 2018 ; Vol. 114. pp. 281–295.
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An algorithm for gradient-based dynamic optimization of UV flash processes. / Ritschel, Tobias Kasper Skovborg; Capolei, Andrea; Gaspar, Jozsef; Jørgensen, John Bagterp.

In: Computers & Chemical Engineering, Vol. 114, 2018, p. 281–295.

Research output: Contribution to journalJournal articleResearchpeer-review

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N2 - This paper presents a novel single-shooting algorithm for gradient-based solution of optimal control problems with vapor-liquid equilibrium constraints. Such optimal control problems are important in several engineering applications, for instance in control of distillation columns, in certain two-phase flow problems, and in operation of oil reservoirs. The single-shooting algorithm uses an adjoint method for the computation of gradients. Furthermore, the algorithm uses either a simultaneous or a nested approach for the numerical solution of the dynamic vapor-liquid equilibrium model equations. Two numerical examples illustrate that the simultaneous approach is faster than the nested approach and that the efficiency of the underlying thermodynamic computations is important for the overall performance of the single-shooting algorithm. We compare the performance of different optimization softwareaswellastheperformanceofdifferentcompilersinaLinuxoperatingsystem. Thesetestsindicatethatreal-timenonlinear model predictive control of UV flash processes is computationally feasible.

AB - This paper presents a novel single-shooting algorithm for gradient-based solution of optimal control problems with vapor-liquid equilibrium constraints. Such optimal control problems are important in several engineering applications, for instance in control of distillation columns, in certain two-phase flow problems, and in operation of oil reservoirs. The single-shooting algorithm uses an adjoint method for the computation of gradients. Furthermore, the algorithm uses either a simultaneous or a nested approach for the numerical solution of the dynamic vapor-liquid equilibrium model equations. Two numerical examples illustrate that the simultaneous approach is faster than the nested approach and that the efficiency of the underlying thermodynamic computations is important for the overall performance of the single-shooting algorithm. We compare the performance of different optimization softwareaswellastheperformanceofdifferentcompilersinaLinuxoperatingsystem. Thesetestsindicatethatreal-timenonlinear model predictive control of UV flash processes is computationally feasible.

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