Theses of the doctoral (PhD) dissertation
Extending the model set of stirred vessels
Attila Egedy MSc. in Chemical Engineering
University of Pannonia Doctoral School in Chemical Engineering and Materials Sciences
Supervisors: Tamás Varga PhD assistant lecturer Tibor Chován PhD, lecturer
Department of Process Engineering Veszprém 2013
1. Previous studies, goals Matematical models are widely used for problem solving in the operation of chemical industries. With adequate models the design, development and operational problems can be easily solved. Matematical models with different complexity were developed, from the simple perfectly mixed reactor models to compartment and Computational Fluid Dynamics (CFD) models. Hence the more complex the problem is, the more complex model is needed for solving the problem, thus the tools facilitating the computations with these models are getting used more widely. In the dissertation I would like to present my research aimed at enhancing the tools for modelling stirred vessels. A compartment model structure identification algorithm was developed based on qualitative trend analysis. The algorithm and the developed program are capable of identifying a compartment model for a system based on measured data. The developed video processing based validation methods are capable of the validation of CFD models based on mixing time and particle tracing measurements. During the research experimental apparatus and methods are developed too. The last part of the dissertation focuses on some chemical engineering applications of CFD models. Two case studies were solved, and discussed in detail: an adaptive temperature control of a laboratory heat exchanger, and the hybrid CFD-compartment modelling of a leaching reactor.
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2. Theses 1. I presented that the proposed algorithm facilitating qualitative methods and hydrodynamic measurements is capable of identifying compartment model. a. An algorithm was developed, which automatically identifies compartment model structure and parameters using unique sequences based on qualitative trend analysis, to ease the use of compartment models. b. I proposed filtering rules, that makes easier finding the adequate compartment model structure for a real system. The built-in rules were checked based on engineering fundamentals. c. Based on the proposed algorithm I developed a computer program, which was tested using multiple test examples. The developed method can be widely used, despite the limit of combinatorial explosion in case of higher compartment numbers. Publications: 6, 9, 14, 24 2. I developed CFD model validation methods for transparent vessel, using video processing based mixing time and particle tracing based measurements. a. I created an experiment based mixing time measurement, and a video recording based processing method. The proposed method is capable of tracking the homogeneity changes with minimal user interaction. The reliability of the proposed technique was tested against multiple measurements at different revolution speeds. b. I developed a particle tracing based method for qualitative characterization of developed CFD models. By synchronising two dimensional trajectories I determined three dimensional trajectories. To compare measured and simulated trajectories
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a new visualisation technique based on particle residence frequency in the reactor was proposed. Publications: 2, 4, 5, 8, 10, 12, 13, 15, 16, 20, 25 3.
I presented that a tool based on the the development of a detailed and adequate CFD simulator of a system, can be applied in engineering problem solving procedure. a. I created a detailed CFD model of a laboratory scale heat exchanger. The detailed CFD model was applied to solve an adaptive temperature control problem, concluding that using a CFD model in control practice can lower the measurement need. b. I created a three dimensional hydrodynamic model of a leaching reactor. I defined the connection between the hydrodynamic model and the parameters of the heuristic compartment model which is capable of calculating the component balance. Based on the examination of the validated compartment model I suggested an optimal parameter interval for operating the leaching reactor.
Publications: 1, 3, 7, 11, 17, 18, 19, 22, 23
3. Future plans, applications The compartment model structure identification algorithm can be developed, by the definition of cross streams, or new basic compartments - for example dead space (compartment without flow). In the field of video recording based validation the measurements with more impellers is the next step. With the calculation of the local mixing times, engineers can achieve better understanding in the operation of a reactor. The particle tracing
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video processing method can be extended by using multiple particles, and parallel particle detection. The adaptive control approach can be tested with a device at higher scale (for example a pilot size reactor), where the method can be tested on a more complex system. With modelling multiple metal leaching, a deeper understanding of the processes can be achieved in the field of electrical waste recycling. We are currently studying the effect of geometry changes on the leaching. The methods discussed in the dissertation can be a foundation for further scale-up studies, and after the scale-up eventually to a patent of a technology.
4. List of publications Journal articles: 1.
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2013. Attila Egedy, Tamás Varga, Tibor Chován, CFD based adaptive control of a tubular electrical heater, Politechnica Periodica (sent for review) 2013. Bálint Molnár, Attila Egedy, Tamás Varga, Analysis of mixing efficiency of different impeller geometries based on CFD models, Politechnica Periodica (sent for review) 2013. Attila Egedy, Szabolcs Fogarasi, Tamás Varga, Árpád Imre-Lucaci, Tibor Chován, CFD models in the development of electrical waste recycling technologies, Chemical Engineering Transactions; DOI: 10.3303/CET1335221 2013. Attila Egedy, Tamás Varga, Tibor Chován, Particle Tracing based model validation for CFD models of stirred reactors, Chemical Engineering Transactions, DOI:10.3303/CET1332239 2013. Bálint Molnár, Attila Egedy, Tamás Varga, CFD Model Based Comparison of Mixing Efficiency of Different Impeller Geometries, Chemical Engineering Transactions, DOI:10.3303/CET1332243
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2012. Attila Egedy, Tamás Varga, Tibor Chován, Compartment model structure identification with qualitative methods for a stirred vessel – Matematical and Computer Modelling of Dynamical Systems, DOI: 10.1080/13873954.2012.700939 2012. Attila Egedy, Tamás Varga, Tibor Chován, Examination of temperature probe setup using computational fluid dynamics simulators, Politechnica Periodica, DOI: 0.3311/pp.ch.2012-2.04 2012. Attila Egedy, Tamás Varga, Tibor Chován, Application of models with different complexity for a stirred tank reactor, Hungarian Journal of Industrial Chemistry, ISBN: 0133-0276, 335-339 2011. Attila Egedy, Tamás Varga, Tibor Chován, Compartment model structure identification of stirred reactors based on qualitative method, Acta Agraria Kaposvariensis, 15, 233-244
Conference proceedings: 10. 2012. Attila Egedy, Tamás Varga, Tibor Chován, CFD modelling and video based model validation for a stirred reactor, Computer Aided Chemical Engineering, ISBN: 978-0444-59519-0, 1123-1127 11. 2012. Attila Egedy, Tamás Varga, Tibor Chován, Examination of temperature probe setup using computational fluid dynamics simulators, Műszaki Kémiai Napok 2012. ISBN: 978-615-5044-54-0, 78-84 12. 2012. Attila Egedy, Tamás Varga, Tibor Chován, Video Based Validation Using Particle Tracing Methods for a Stirred Vessel, V. International Interdisciplinary Technical Conference of Young Scientists, Poznan, ISBN: 978-83926896-4-5, 49-54 13. 2011. Attila Egedy, Tamás Varga, Tibor Chován, Investigations on Hydrodynamics in a Stirred Tank for Educational Purposes, COMSOL Conference Stuttgart 14. 2011. Attila Egedy, Tamás Varga, Tibor Chován, Model Structure Identification Algorithm for Stirred Systems, IV. International Interdisciplinary Technical Conference of
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Young Scientists, Poznan, ISBN:978-83-926896-3-8, 242246 15. 2011. Attila Egedy, Tamás Varga, Tibor Chován, Kevert reaktorok dinamikai viselkedésének vizsgálata, Műszaki Kémiai Napok 2011. ISBN: 978-615-5004-07-6, 231-236 16. 2010. Attila Egedy, Tamás Varga, Tibor Chován, Kevert bioreaktorok hidrodinamikai modellezése, Műszaki Kémiai Napok 2010. ISBN: 978-963-9696-93-8, 193-198 Lectures, posters: 17. 2013. július - Attila Egedy, Szabolcs Fogarasi, Tamás Varga, Árpád Imre-Lucaci, Tibor Chován, CFD szimuláció alkalmazása elektronikai hulladék hasznosítási technológiák fejlesztésében, „Környezetbarát anyagok és technológiák” konferencia, Veszprém 18. 2013. június - Attila Egedy, Szabolcs Fogarasi, Tamás Varga, Árpád Imre-Lucaci, Tibor Chován, CFD modellezés a hulladékhasznosító technológiák fejlesztésében, „Jubileumi Lóczy Lajos emlékkonferencia 1913–2013” Sekély vizű tavas területek ökológiája, szociológiája és komplex mérnöki elemzése, Kaposvár. 19. 2013. április – Attila Egedy, Tamás Varga, Tibor Chován, CFD model based adaptive control of tubular electrical heater, Műszaki Kémiai Napok 2013., Veszprém, Magyarország 20. 2012. november – Attila Egedy, Tamás Varga, Tibor Chován: Fermentációs reaktor vizsgálata numerikus áramlástani módszerekkel, XVIII. Nemzetközi Vegyészkonferencia, Félixfürdő, Románia 21. 2012. november – György Rádi, Attila Egedy, Tamás Varga, Tibor Chován: Katalizátor ágy üres keresztmetszeti tényező radiális eloszlásának vizsgálata, XVIII. Nemzetközi Vegyészkonferencia, Félixfürdő, Románia 22. 2012. Attila Egedy, Tamás Varga, Tibor Chován, CFD Model Based Control Algorithm Development of a Laboratory Water Heater, CAPE Forum 2012, Veszprém, Magyarország
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23. 2012. Attila Egedy, Tamás Varga, Tibor Chován, CFD Modelling and Validation of a Laboratory Water Heater, IX. Meeting of Young Chemical Engineers, Zágráb, Horvátország 24. 2011. Attila Egedy, Tamás Varga, Tibor Chován, Struktúra identifikáció kevert tankokban cellás modellek és kvalitatív módszerek alkalmazásával, IX. Alkalmazott Informatikai konferencia, Kaposvár, Magyarország 25. 2010. Attila Egedy, Tamás Varga, Tibor Chován, Kevert bioreaktorok hidrodinamikai modellezése, IV. SzentGyörgyi Albert Konferencia, Budapest, Magyarország
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