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Computer-aided optimization of complex processes in production systems and urban environments

Yamanee-Nolin, Mikael LU (2020)
Abstract
Complex processes can be seen as a series of actions, changes, and/or events that are related in different temporospatial manners, and thus are potentially difficult to understand. Optimizing such a process is therefore not necessarily a simple feat, and doing it experimentally may become both time-consuming and expensive. Computer-aided optimization therefore lends itself as a viable alternative, since it can be performed in a relatively short time at a low cost, whilst providing insights into how to improve a process.

The work collected and presented in this thesis concerns three different complex processes in the two categories of production systems, and urban environments, all in need of improvements. These three cases have... (More)
Complex processes can be seen as a series of actions, changes, and/or events that are related in different temporospatial manners, and thus are potentially difficult to understand. Optimizing such a process is therefore not necessarily a simple feat, and doing it experimentally may become both time-consuming and expensive. Computer-aided optimization therefore lends itself as a viable alternative, since it can be performed in a relatively short time at a low cost, whilst providing insights into how to improve a process.

The work collected and presented in this thesis concerns three different complex processes in the two categories of production systems, and urban environments, all in need of improvements. These three cases have thus been the subjects of a series of studies collected and presented in this thesis, appended as Papers I-IX. For production systems, two cases are presented. The first case is the purification of a polyalcohol at Perstorp AB, the process of which was subject to process-disturbing oscillations that were analyzed and their effects quantified through an in-silico sensitivity analysis, and subsequently reduced by 99.7% via a computer-aided dynamic optimization approach. Secondly, the chromatographic purification of pharmaceuticals has been studied, where optimization techniques were used for the dynamic optimization of the loading phase of a capture step as well as the optimal design of integrated column sequences. In the category of urban environments, blue-green systems for urban flooding mitigation in the city of Malmö have been studied, where a model was developed and then applied for optimal economic siting and sizing of retrofits taking into account implementation and flooding-induced costs. With a 3% decrease in costs, whilst modest, this result shows that the blue-green systems are economical alternatives to consider for mitigating urban flooding.

The purpose of this thesis – in addition to improving the three aforementioned processes – is to provide tools, in the form of a procedure and a framework, that can be used to increase the accessibility of computer-aided optimization. The aim is that these tools can be useful to practitioners and facilitate studies, which in turn can be used as a foundation for improving any given complex situation or process. In addition, a summary is presented of the most important parts of an optimization problem and its formulation, and the most relevant optimization approaches to the work presented in this thesis are also summarized and explained. Furthermore, the presented tools are used to describe and analyze the work that has been performed and is presented in this thesis. They are also used to explain how the choices that are made regarding tools for modeling, simulation, and optimization may impact each other, and thus have an interplay. With these
general and generalizable tools, the aim is to contribute towards an increased understanding and thereby accessibility of computer-aided optimization. (Less)
Abstract (Swedish)
Visst vore det fint om vi kunde producera nödvändiga kemikalier mer effektivt, förse alla människor med de läkemedel de behöver till en lägre kostnad än vad som är möjligt idag, och förhindra översvämningar i stadsmiljö? Men vad har dessa tre ting gemensamt, egentligen? Jo, att man kan optimera de olika processer som ligger bakom alla tre! Processer finns i princip överallt i världen, komplexa som enkla, konkreta som ab strakta. Att optimera en process innebär att vi försöker förbättra den och göra den så bra som bara är möjligt. Om detta ska göras via experiment kan det dock ta väldigt lång tid och även bli väldigt dyrt – och ibland är det till och med praktiskt omöjligt. Ett gångbart alternativ är då att ta hjälp av modern beräkningskraft... (More)
Visst vore det fint om vi kunde producera nödvändiga kemikalier mer effektivt, förse alla människor med de läkemedel de behöver till en lägre kostnad än vad som är möjligt idag, och förhindra översvämningar i stadsmiljö? Men vad har dessa tre ting gemensamt, egentligen? Jo, att man kan optimera de olika processer som ligger bakom alla tre! Processer finns i princip överallt i världen, komplexa som enkla, konkreta som ab strakta. Att optimera en process innebär att vi försöker förbättra den och göra den så bra som bara är möjligt. Om detta ska göras via experiment kan det dock ta väldigt lång tid och även bli väldigt dyrt – och ibland är det till och med praktiskt omöjligt. Ett gångbart alternativ är då att ta hjälp av modern beräkningskraft och istället utföra modellbaserade optimeringsstudier med hjälp av datorn, d.v.s. datorstödda optimeringsstudier. För detta ändamål krävs en matematisk modell som behöver simuleras för att vi på så sätt ska kunna få ut användbar information om vår verkliga process som vi kan basera vår optimering på.

I denna avhandling presenteras en övergripande, allmängiltig procedur och ett slags ramverk tillsammans med ett antal optimeringsmetoder som kombinerat kan användas som verktyg för att effektivt utföra datorstödda optimeringsstudier. Dessa verktyg baseras dels på sedan tidigare publicerad litteratur, men också på arbetet som samlas och presenteras i denna avhandling, och målet är att de ska kunna användas som hjälp för att förbättra i princip vilken verklig situation som helst.

Det samlade arbetet ger också en fingervisning om vilka resultat man kan nå via datorstödda optimeringsstudier. Till exempel så används kommersiellt tillgängliga datorprogram för att skapa modeller. Sedan används dessa modeller för att undersöka och stabilisera en process för kemikalieproduktion. Denna process led tidigare av störningar som orsakade lägre produktivitet och större energiåtgång, vilka i princip eliminerades. Vidare har även en typ av läkemedelsproduktion förbättrats genom att matematiska modeller använts för att visa hur man på bästa sätt bör skapa och köra en särskild typ av process för läkemedelsupprening, vilket i slutändan ger billigare mediciner. Slutligen har även så kallade blå-gröna system undersökts, vilket exempelvis är dammar och gröna tak som används för att minska risken för översvämningar. Dessa har modellerats för att ta reda på var man bör bygga sådana system i Malmö stad, och hur stora de bör vara, för att förhindra översvämningar utan att det blir onödigt dyrt. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Bogle, David, University College London, United Kingdom.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Optimization, modeling, simulation, complex processes, process systems engineering, preparative chromatography, blue-green systems
pages
209 pages
publisher
Department of Chemical Engineering, Lund University
defense location
Lecture hall KC:A, Kemicentrum, Naturvetarvägen 14, Faculty of Engineering LTH, Lund University, Lund. Follow online: https://youtu.be/LIp0d5pSSp0
defense date
2020-05-08 9:15:00
ISBN
978-91-7422-733-8
978-91-7422-732-1
project
Blue-green stormwater systems for citywide flood mitigation: modeling, and evaluation
language
English
LU publication?
yes
id
82c0adc8-aa82-49ba-ba25-b13d2743f544
date added to LUP
2020-04-02 10:52:23
date last changed
2020-04-16 10:30:09
@phdthesis{82c0adc8-aa82-49ba-ba25-b13d2743f544,
  abstract     = {Complex processes can be seen as a series of actions, changes, and/or events that are related in different temporospatial manners, and thus are potentially difficult to understand. Optimizing such a process is therefore not necessarily a simple feat, and doing it experimentally may become both time-consuming and expensive. Computer-aided optimization therefore lends itself as a viable alternative, since it can be performed in a relatively short time at a low cost, whilst providing insights into how to improve a process.<br/><br/>The work collected and presented in this thesis concerns three different complex processes in the two categories of production systems, and urban environments, all in need of improvements. These three cases have thus been the subjects of a series of studies collected and presented in this thesis, appended as Papers I-IX. For production systems, two cases are presented. The first case is the purification of a polyalcohol at Perstorp AB, the process of which was subject to process-disturbing oscillations that were analyzed and their effects quantified through an in-silico sensitivity analysis, and subsequently reduced by 99.7% via a computer-aided dynamic optimization approach. Secondly, the chromatographic purification of pharmaceuticals has been studied, where optimization techniques were used for the dynamic optimization of the loading phase of a capture step as well as the optimal design of integrated column sequences. In the category of urban environments, blue-green systems for urban flooding mitigation in the city of Malmö have been studied, where a model was developed and then applied for optimal economic siting and sizing of retrofits taking into account implementation and flooding-induced costs. With a 3% decrease in costs, whilst modest, this result shows that the blue-green systems are economical alternatives to consider for mitigating urban flooding.<br/><br/>The purpose of this thesis – in addition to improving the three aforementioned processes – is to provide tools, in the form of a procedure and a framework, that can be used to increase the accessibility of computer-aided optimization. The aim is that these tools can be useful to practitioners and facilitate studies, which in turn can be used as a foundation for improving any given complex situation or process. In addition, a summary is presented of the most important parts of an optimization problem and its formulation, and the most relevant optimization approaches to the work presented in this thesis are also summarized and explained. Furthermore, the presented tools are used to describe and analyze the work that has been performed and is presented in this thesis. They are also used to explain how the choices that are made regarding tools for modeling, simulation, and optimization may impact each other, and thus have an interplay. With these<br/>general and generalizable tools, the aim is to contribute towards an increased understanding and thereby accessibility of computer-aided optimization.},
  author       = {Yamanee-Nolin, Mikael},
  isbn         = {978-91-7422-733-8},
  language     = {eng},
  month        = {04},
  publisher    = {Department of Chemical Engineering, Lund University},
  school       = {Lund University},
  title        = {Computer-aided optimization of complex processes in production systems and urban environments},
  url          = {https://lup.lub.lu.se/search/ws/files/77971082/Spikfil_MPDYN.pdf},
  year         = {2020},
}