The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.

Studies on Computer Aided Process and Equipment Design in Process Industry

Elina Pajula

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Chemical Technology for public examination and debate in Auditorium KE2 at Helsinki University of Technology (Espoo, Finland) on the 15th of December, 2006, at 12 o'clock noon.

Overview in PDF format (ISBN 951-22-8489-8)   [728 KB]
Dissertation is also available in print (ISBN 951-22-8488-X)


The challenge in design is to create a process or equipment for future needs. The changing world and keen competition bring about challenges such as a faster project time which means, on one hand, the need to utilize both earlier designs and organizational memory, on the other hand, that creativity should be supported to create competitive designs. At the same time requirements for a robust design in which uncertainties exist need to be taken into account.

The thesis presents new methods and application examples to answer the challenges. Case-based reasoning (CBR) provides a method for fast process and equipment design by utilizing earlier knowledge systematically. In new designs feedback from earlier experiences is taken into account, and a creative aspect can be included by the use of analogies. The thesis presents new method for CBR-based separation process synthesis and a CBR-based method for combinatorial mixer equipment design from parts.

A further challenge in design is how to create a robust and flexible design capable of operating in changing situations. The challenge has been dealt with scenario-based approaches and stochastic simulation. Three new applications are presented: Scenario-based approaches for thermo-mechanical pulp plant design in the presence of demand uncertainty and paper machine consistency control with an uncertainty in head box consistency control measurement. Stochastic simulation has been applied to paper machine broke tank level control, where the uncertainty is caused by paper machine breaks.

This thesis consists of an overview and of the following 8 publications:

  1. Pajula, E., Seuranen, T., Koiranen, T., Hurme, M., Synthesis of separation processes by using case-based reasoning, Computers and Chemical Engineering 25 (2001) 775-782. © 2001 Elsevier Science. By permission.
  2. Seuranen, T., Pajula, E., Hurme, M., Synthesis of azeotropic separation systems by case-based reasoning, Computer-Aided Chemical Engineering, Vol. 10, Elsevier 2002, 343-348. © 2002 Elsevier Science. By permission.
  3. Pajula, E., Seuranen, T., Hurme, M., Selection of separation sequences by case-based reasoning, Computer-Aided Chemical Engineering, Vol. 9, Elsevier 2001, 469-474. © 2001 Elsevier Science. By permission.
  4. Seuranen, T., Hurme, M., Pajula, E., Synthesis of separation processes by case-based reasoning, Computers and Chemical Engineering 29 (2005) 1473-1482. © 2005 Elsevier Science. By permission.
  5. Pajula, E., Koiranen, T., Seuranen, T., Hurme, M., Computer aided process equipment design from equipment parts, Computers and Chemical Engineering 23 (1999) Supplement S683-S686. © 1999 Elsevier Science. By permission.
  6. Sundqvist, S., Pajula, E., Ritala, R., Risk premium and robustness in design optimization of simplified TMP plant, Computer-Aided Chemical Engineering, Vol. 14, Elsevier 2003, 311-316. © 2003 Elsevier Science. By permission.
  7. Pajula, E., Ritala, R., Measurement uncertainty in integrated control and process design – a case study, Chemical Engineering and Processing 45 (2006) 312-322. © 2006 Elsevier Science. By permission.
  8. Pajula, E., Tienari, M., Studying broke tank averaging level control with stochastic simulator, Proceedings of the Control Systems 2006 Conference, ed. R. Ritala, Tampere University of Technology, Tampere 2006, pp. 43-48. © 2006 Finnish Society of Automation. By permission.

Keywords: case-based reasoning, process design, uncertainty, equipment design

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© 2006 Helsinki University of Technology

Last update 2011-05-26