Numerical Simulation of Reactive Crystallization in Stirred Tank Reactors

dc.contributorAalto-yliopistofi
dc.contributorAalto Universityen
dc.contributor.advisorBuffo, Antonio, Prof., Politecnico di Torino, Italy
dc.contributor.authorZhao, Wenli
dc.contributor.departmentKemian tekniikan ja metallurgian laitosfi
dc.contributor.departmentDepartment of Chemical and Metallurgical Engineeringen
dc.contributor.labResearch Group of Chemical Engineeringen
dc.contributor.schoolKemian tekniikan korkeakoulufi
dc.contributor.schoolSchool of Chemical Engineeringen
dc.contributor.supervisorAlopaeus, Ville, Prof., Aalto University, Department of Chemical and Metallurgical Engineering, Finland
dc.date.accessioned2018-03-29T09:02:48Z
dc.date.available2018-03-29T09:02:48Z
dc.date.defence2018-04-20
dc.date.issued2018
dc.description.abstractModel development is essential for design and scale up of multiphase chemical reactors to provide a better understanding of physical and chemical phenomena between phases at different scales. Mathematical descriptions of the reactive crystallization include mass transfer, chemical reaction, crystallization kinetics, population balance and hydrodynamics, which consist of a set of partial differential equations with high nonlinearity. A full simulation with a commercial computational fluid dynamics (CFD) software is possible with existing computational resources but not desirable during the initial stage of reactor design. The purpose of this thesis is to explore the mechanism of multiphase reactive crystallization and develop a compartmental model to combine hydrodynamics and detailed reaction efficiently. The chemical system of CO2(G)-H2O(L)-Mg(OH)2(S) is chosen as the practical application to reveal mechanisms of multiphase reactive crystallization, which couple the reactive dissolution, chemical absorption and crystallization. As modeling of such complex system is challenging, the reactive dissolution of Mg(OH)2(S) in HCl(aq) and reactive crystallization of CaCO3(S) from CO2(G) and Ca(OH)2(aq) system are studied separately. The first part of the thesis introduces the gas-liquid and solid-liquid mass transfer models based on two-film theory and Nernst-Planck electroneutrality. In addition, enhancement factor is adopted to modify mass transfer fluxes when chemical reaction occurs in liquid film. Then, population balance model is presented along with several solution techniques to calculate particle size distributions of gas bubbles and final crystal products. The closure models include nucleation and growth of crystals, breakage, coalescence and agglomeration of gas bubbles and crystals. Finally, a compartmental model combining the flow field obtained by CFD simulation and reaction mechanisms is constructed to estimate the influence of flow field on multiphase crystallization. The compartmental modelling results show that heterogeneous mixing has a strong influence on local mass transfer rates and size distribution of final crystal products. By appropriate division of the fluid domain, compartmental model can offer a more efficient simulation for reactive crystallization without the limitation of chemical components and geometries of different reactors. This characteristic highlights the potential extensibility and portability of compartmental model in reactor design and scale up.en
dc.format.extent94 + app. 50
dc.format.mimetypeapplication/pdfen
dc.identifier.isbn978-952-60-7916-5 (electronic)
dc.identifier.isbn978-952-60-7915-8 (printed)
dc.identifier.issn1799-4942 (electronic)
dc.identifier.issn1799-4934 (printed)
dc.identifier.issn1799-4934 (ISSN-L)
dc.identifier.urihttps://aaltodoc.aalto.fi/handle/123456789/30491
dc.identifier.urnURN:ISBN:978-952-60-7916-5
dc.language.isoenen
dc.opnKoiranen, Tuomas, Prof., Lappeenranta University of Technology, Finland
dc.publisherAalto Universityen
dc.publisherAalto-yliopistofi
dc.relation.haspart[Publication 1]: Zhao Wenli, Han Bing, Jakobsson Kaj, Louhi-Kultanen Marjatta, Alopaeus Ville. Mathematical model of crystallization of magnesium carbonate with carbon dioxide from the magnesium hydroxide slurry. Computers & Chemical Engineering, 2016, 87, 180-189. DOI: 10.1016/j.compchemeng.2016.01.013
dc.relation.haspart[Publication 2]: Zhao Wenli, Jama Ali Mohamed, Buffo Antonio, Alopaeus Ville. Population balance model and experimental validation for reactive dissolution of particle agglomerates. Computers & Chemical Engineering, 2018, 108, 240-249. DOI: 10.1016/j.compchemeng.2017.09.019
dc.relation.haspart[Publication 3]: Zhao Wenli, Buffo Antonio, Alopaeus Ville, Bing Han, Marjatta Louhi-Kultanen. Application of the Compartmental Model to the Gas–Liquid Crystallization of CO2-Ca(OH)2 Aqueous System in a Stirred Tank. AIChE Journal 2017, 63, 378-386. DOI: 10.1002/aic.15567
dc.relation.haspart[Publication 4]: Guo Zhichao, Han Wenxiang, Zhao Wenli, Li Liye, Wang Baodong, Xiao Yongfeng, Alopaeus Ville. The effect of microwave on the crystallization process of magnesium carbonate from aqueous solutions. Powder Technology, 2018, 328, 358-366. DOI: 10.1016/j.powtec.2018.01.038
dc.relation.ispartofseriesAalto University publication series DOCTORAL DISSERTATIONSen
dc.relation.ispartofseries56/2018
dc.revMarchisio, Daniele, Prof., Politecnico di Torino, Italy
dc.revWei, Hongyuan, Prof., Tianjin University, China
dc.subject.keywordcrystallizationen
dc.subject.keywordCFDen
dc.subject.keywordpopulation balanceen
dc.subject.keywordcompartmental modelingen
dc.subject.otherChemistryen
dc.subject.otherMetallurgyen
dc.titleNumerical Simulation of Reactive Crystallization in Stirred Tank Reactorsen
dc.typeG5 Artikkeliväitöskirjafi
dc.type.dcmitypetexten
dc.type.ontasotDoctoral dissertation (article-based)en
dc.type.ontasotVäitöskirja (artikkeli)fi
local.aalto.acrisexportstatuschecked 2019-02-23_1044
local.aalto.archiveyes
local.aalto.formfolder2018_03_28_klo_17_01

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