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Trajectory optimization of an oscillating industrial two-stage evaporator utilizing a Python-Aspen Plus Dynamics toolchain

Yamanee-Nolin, Mikael LU ; Andersson, Niklas LU orcid ; Nilsson, Bernt LU ; Max-Hansen, Mark LU and Pajalic, Oleg (2020) In Chemical Engineering Research and Design 155. p.12-17
Abstract

Evaporators are integral parts of many separation processes across production industries, and they need to be well understood in order to be operated well, thereby enabling high resource-efficiency and productivity. In a previous investigation, the effects of disturbing oscillations in a two-stage evaporator system were quantified. In the current study, these oscillations were reduced through trajectory optimization using steam consumption as a temporally discretized decision variable, taking advantage of a dynamic process flowsheet model in Aspen Plus Dynamics (APD) employed as if it were a black-box model. The optimization was performed utilizing a Python-APD toolchain with the SciPy implementation of COBYLA. The optimal trajectory... (More)

Evaporators are integral parts of many separation processes across production industries, and they need to be well understood in order to be operated well, thereby enabling high resource-efficiency and productivity. In a previous investigation, the effects of disturbing oscillations in a two-stage evaporator system were quantified. In the current study, these oscillations were reduced through trajectory optimization using steam consumption as a temporally discretized decision variable, taking advantage of a dynamic process flowsheet model in Aspen Plus Dynamics (APD) employed as if it were a black-box model. The optimization was performed utilizing a Python-APD toolchain with the SciPy implementation of COBYLA. The optimal trajectory was able to successfully reduce the objective function value (including the product stream mass flow variance and a bang-bang penalty on the trajectory itself) to slightly less than 0.3 % of that of the nominal case, in which a time-invariant steam consumption was employed. This in turn grants opportunities to increase throughput of the process, leading to significant financial gains.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Aspen Plus Dynamics, Derivative-free optimization, Dynamic optimization, Evaporator system, Oscillations, Python
in
Chemical Engineering Research and Design
volume
155
pages
6 pages
publisher
Institution of Chemical Engineers
external identifiers
  • scopus:85077921557
ISSN
0263-8762
DOI
10.1016/j.cherd.2019.12.015
language
English
LU publication?
yes
id
c3634d7a-564d-4cda-b291-f91e0405ccf1
date added to LUP
2020-01-24 10:43:49
date last changed
2023-12-04 07:46:40
@article{c3634d7a-564d-4cda-b291-f91e0405ccf1,
  abstract     = {{<p>Evaporators are integral parts of many separation processes across production industries, and they need to be well understood in order to be operated well, thereby enabling high resource-efficiency and productivity. In a previous investigation, the effects of disturbing oscillations in a two-stage evaporator system were quantified. In the current study, these oscillations were reduced through trajectory optimization using steam consumption as a temporally discretized decision variable, taking advantage of a dynamic process flowsheet model in Aspen Plus Dynamics (APD) employed as if it were a black-box model. The optimization was performed utilizing a Python-APD toolchain with the SciPy implementation of COBYLA. The optimal trajectory was able to successfully reduce the objective function value (including the product stream mass flow variance and a bang-bang penalty on the trajectory itself) to slightly less than 0.3 % of that of the nominal case, in which a time-invariant steam consumption was employed. This in turn grants opportunities to increase throughput of the process, leading to significant financial gains.</p>}},
  author       = {{Yamanee-Nolin, Mikael and Andersson, Niklas and Nilsson, Bernt and Max-Hansen, Mark and Pajalic, Oleg}},
  issn         = {{0263-8762}},
  keywords     = {{Aspen Plus Dynamics; Derivative-free optimization; Dynamic optimization; Evaporator system; Oscillations; Python}},
  language     = {{eng}},
  month        = {{03}},
  pages        = {{12--17}},
  publisher    = {{Institution of Chemical Engineers}},
  series       = {{Chemical Engineering Research and Design}},
  title        = {{Trajectory optimization of an oscillating industrial two-stage evaporator utilizing a Python-Aspen Plus Dynamics toolchain}},
  url          = {{http://dx.doi.org/10.1016/j.cherd.2019.12.015}},
  doi          = {{10.1016/j.cherd.2019.12.015}},
  volume       = {{155}},
  year         = {{2020}},
}