Numerical Simulation of Reactive Crystallization in Stirred Tank Reactors

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Buffo, Antonio, Prof., Politecnico di Torino, Italy Zhao, Wenli 2018-03-29T09:02:48Z 2018-03-29T09:02:48Z 2018
dc.identifier.isbn 978-952-60-7916-5 (electronic)
dc.identifier.isbn 978-952-60-7915-8 (printed)
dc.identifier.issn 1799-4942 (electronic)
dc.identifier.issn 1799-4934 (printed)
dc.identifier.issn 1799-4934 (ISSN-L)
dc.description.abstract Model 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.extent 94 + app. 50
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher Aalto University en
dc.publisher Aalto-yliopisto fi
dc.relation.ispartofseries Aalto University publication series DOCTORAL DISSERTATIONS en
dc.relation.ispartofseries 56/2018
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.subject.other Chemistry en
dc.subject.other Metallurgy en
dc.title Numerical Simulation of Reactive Crystallization in Stirred Tank Reactors en
dc.type G5 Artikkeliväitöskirja fi Kemian tekniikan korkeakoulu fi School of Chemical Technology en
dc.contributor.department Kemian tekniikan ja metallurgian laitos fi
dc.contributor.department Department of Chemical and Metallurgical Engineering en
dc.subject.keyword crystallization en
dc.subject.keyword CFD en
dc.subject.keyword population balance en
dc.subject.keyword compartmental modeling en
dc.identifier.urn URN:ISBN:978-952-60-7916-5
dc.type.dcmitype text en
dc.type.ontasot Doctoral dissertation (article-based) en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.contributor.supervisor Alopaeus, Ville, Prof., Aalto University, Department of Chemical and Metallurgical Engineering, Finland
dc.opn Koiranen, Tuomas, Prof., Lappeenranta University of Technology, Finland
dc.contributor.lab Research Group of Chemical Engineering en
dc.rev Marchisio, Daniele, Prof., Politecnico di Torino, Italy
dc.rev Wei, Hongyuan, Prof., Tianjin University, China 2018-04-20
local.aalto.acrisexportstatus checked 2019-02-23_1044

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