Use Of Cfd For The Extrapolation Of Attrition And Hydrodynamic Phenomena In Circulating Fluidized Beds
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Use Of Cfd For The Extrapolation Of Attrition And Hydrodynamic Phenomena In Circulating Fluidized Beds
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Author : Benjamin Amblard
language : en
Publisher:
Release Date : 2020
Use Of Cfd For The Extrapolation Of Attrition And Hydrodynamic Phenomena In Circulating Fluidized Beds written by Benjamin Amblard and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
Extrapolation from lab to industrial scale is challenging when dealing with Circulating Fluidized Bed (CFB) processes and technologies. Extrapolation relates in a first step, to the understanding of physical phenomena at accessible scales through dedicated experiments. In a second step, modeling is often used to transpose observation from lab scale to an industrial perspective. In my Ph.D. project, we present how Computational Fluid Dynamic (CFD) tools can be used for both steps with first the characterization of local phenomena at lab scale and second for the scale extrapolation of hydrodynamic phenomena. Concerning the first topic, it is essential in the early stage of the process development, to quantify attrition phenomena expected at industrial scale when selecting the solid particles to be used. We faced this situation during the development of the Chemical Looping Combustion (CLC) process with the choice of the oxygen carrier particles. We then proposed a new procedure using a jet cup apparatus to compare the mechanical resistance to attrition of particles used in the CLC process with particles used in the Fluid Catalytic Cracking (FCC) process. The latter is then used as a reference since attrition data are available both at lab and industrial scales for FCC catalyst. We used CFD tools for the understanding of local physical phenomena to then orientate the experimental strategy to compare the mechanical resistance to attrition of the different powders of interest (equilibrium FCC catalyst and fresh and equilibrium oxygen carriers). The results obtained showed that the fresh and equilibrium oxygen carriers performed respectively better and worse than the reference FCC catalyst. This experimental procedure can therefore be used in the future to evaluate the mechanical resistance of other oxygen carriers. The main perspective is then to correlate lab scale experimentation with the main sources of attrition in CFBs for finally implementing a population balance modeling to assess attrition at industrial scale.Concerning the second topic on hydrodynamic phenomena extrapolation, we propose a simulation strategy in order to assess the CFD models extrapolation capability and their potential limits in term of fluidization regimes representativeness. For this purpose, different experimental set ups were used with a 20 cm and 90 cm turbulent fluidized beds and a 30 cm riser to characterize transport regime conditions. In the three experiments, FCC catalysts with similar physical properties were used. Local and global experimental flow characterizations were acquired to then evaluate the predictions of two CFD approaches: the Multiphase Particle In Cell (MP-PIC) approach with the software Barracuda VR® and the Euler/Euler with the Kinetic Theory of Granular Flows using openFOAM. In the first step, we developed dedicated drag laws to get satisfactory hydrodynamic predictions of the 20 cm fluidized bed hydrodynamic. In the next step, the CFD model parameters developed were applied for the 90 cm fluidized bed simulation. This step was crucial since it was a differentiator between both approaches with the parameters developed for Barracuda VR® failing to predict the bed hydrodynamic while the parameters developed for openFOAM gave satisfying results. These results justify the evaluation of CFD models at different scales and also show that CFD can be used for extrapolation. In the last step, the openFOAM modeling parameters developed were applied for the simulation of the riser transport regime. The simulation failed capturing the riser hydrodynamic and a dedicated drag law was then developed to capture reasonably well these riser experimental data. These results show the importance of investigating the limits of the models developed. For the perspectives, the same strategy could be applied for the predictions of pressure and temperature effects with the final objective being to simulate an industrial fluidized bed.
Computational Fluid Dynamics Cfd Simulation Of A Gas Solid Fluidized Bed Residence Time Validation Study
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Author : Baru Debtera
language : en
Publisher:
Release Date : 2021-11-05
Computational Fluid Dynamics Cfd Simulation Of A Gas Solid Fluidized Bed Residence Time Validation Study written by Baru Debtera and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-11-05 with categories.
Academic Paper from the year 2021 in the subject Physics - Mechanics, language: English, abstract: In this study, numerical simulations of a gas-solid fluidized bed reactor involving a two-fluid Eulerian multiphase model and incorporating the Kinetic Theory of Granular Flow (KTGF) for the solids phase have been performed using a commercial Computational Fluid Dynamics (CFD) software. The fluidized bed setup consists of 1,5 m height and 0,2 m diameter in which a series of experiments were performed using Helium tracer to determine the Residence Time Distribution (RTD) at various normalized velocities i.e., with different degrees of gas-solids mixing. Both 2D and 3D simulations of the fluidized bed reactor are performed. The main purpose of this study is to understand the hydrodynamic behavior of a gas-solid fluidized bed reactor through a framework of Eulerian multiphase model and to analyze hydrodynamic behavior of the gas-solids mixing.
Cfd Simulation Of Hydrodynamics Of Three Phase Fluidized Bed
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Author :
language : en
Publisher:
Release Date :
Cfd Simulation Of Hydrodynamics Of Three Phase Fluidized Bed written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on with categories.
The gas-liquid-solid fluidized bed has emerged in recent years as one of the most promising devices for three-phase operation. Such a device is of considerable industrial importance as evident from its wide application in chemical, refining, petrochemical, biochemical processing, pharmaceutical and food industries. Selection and design is one of the main parameter in the performance of three phase system. Success is dependent on the effective contact between the phases. Even though a large number of experimental studies have been done in different process parameters and physical properties, the complex hydrodynamics of three phase fluidized bed reactors are not well understood due to complicated phenomena such as particle- article, liquid- article and particle- ubble interactions. For this reason, computational fluid dynamics (CFD) has been promoted as a useful tool for understanding multiphase reactors for precise design and scale up. In the present work three different configuration of cylindrical column has been taken for studying co-current gas-liquid-solid fluidization with the help of commercial CFD codes as FLUENT. The main focus for analyzing the results is on the column with 1.88 m height and diameter of 0.1 m containing solid particles as glass beads of size 2.18 mm and 4.05 mm. In the present study of three phase fluidized simulation the hydrodynamic parameters investigated includes phase hold up, velocity profiles of all phases, bed expansion, bed voidage, static pressure drop, frictional pressure drop at wall, and energy flows. The operating variables varied includes liquid and air inlet velocity, initial solid static bed height and particle size. The dynamic characteristics obtained from CFD simulation have been validated with the experimental results and a good agreement has been observed. Eulerian-Eulerian granular multiphase flow approach is capable of predicting the overall performance of gas- iquid- olid fluidized bed. The expanded bed height is s.
Cfd Modeling Of Hydrodynamics Of Fluidized Bed
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Author :
language : en
Publisher:
Release Date :
Cfd Modeling Of Hydrodynamics Of Fluidized Bed written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on with categories.
The objective of this project is to simulate a gas-solid fluidized by applying CFD techniques in order to investigate hydrodynamics and heat transfer phenomena. Reactor model predictions will be compared with the corresponding experimental data reported in the literature to validate the model . To simulate a gas-solid fluidized bed we need to use the multiphase flow approach . First we have to write the equations for the different flow regimes and then different CFD techniques are applied for discretization of those equations. After that a code is written for calculating the values of volume fraction, velocity and temperature.
Engineering Applications Of Computational Fluid Dynamics
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Author : Maher Al-Baghdadi
language : en
Publisher:
Release Date : 2012-08-02
Engineering Applications Of Computational Fluid Dynamics written by Maher Al-Baghdadi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-08-02 with categories.
Computational Fluid Dynamics (CFD) is the science of predicting fluid flow, heat transfer, mass transfer, phase change, chemical reaction, mechanical movement, stress or deformation of related solid structures, and related phenomena by solving the mathematical equations that govern these processes using a numerical algorithm on a computer. The results of CFD analyses are relevant in: conceptual studies of new designs, detailed product development, troubleshooting, and redesign. CFD analysis complements testing and experimentation, by reduces the total effort required in the experiment design and data acquisition. CFD complements physical modelling and other experimental techniques by providing a detailed look into our fluid flow problems, including complex physical processes such as turbulence, chemical reactions, heat and mass transfer, and multiphase flows. In many cases, we can build and analyze virtual models at a fraction of the time and cost of physical modelling. This allows us to investigate more design options and "what if" scenarios than ever before. Moreover, flow modelling provides insights into our fluid flow problems that would be too costly or simply prohibitive by experimental techniques alone. The added insight and understanding gained from flow modelling gives us confidence in our design proposals, avoiding the added costs of over-sizing and over-specification, while reducing risk.The use of Computational Fluid Dynamics to simulate engineering phenomena continues to grow throughout many engineering disciplines. On the back of ever more powerful computers and graphical user interfaces CFD provides engineers with a reliable tool to assist in the design of industrial equipment often reducing or eliminating the need for performing trial-and-error experimentation.In summary, much progress has been made in engineering applications of CFD. The chapters in this book testify to the vitality of engineering CFD research and demonstrate the considerable potential for use of these techniques in the future. The book is intended to serve as a reference for both researchers and postgraduate students.
Combustion And Gasification In Fluidized Beds
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Author : Prabir Basu
language : en
Publisher: CRC Press
Release Date : 2006-02-17
Combustion And Gasification In Fluidized Beds written by Prabir Basu and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-02-17 with Science categories.
Besides being one of the best Clean Coal Technologies, fluidized beds are also proving to be the most practical option for biomass conversion. Although the technology is well established, the field lacks a comprehensive guide to the design and operating principles of fluidized bed boilers and gasifiers. With more than 30 years of research and indus
Essentials Of Fluidization Technology
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Author : John R. Grace
language : en
Publisher: John Wiley & Sons
Release Date : 2020-06-15
Essentials Of Fluidization Technology written by John R. Grace and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-06-15 with Technology & Engineering categories.
A concise and clear treatment of the fundamentals of fluidization, with a view to its applications in the process and energy industries.
Proceedings Of The 20th International Conference On Fluidized Bed Combustion
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Author : Guangxi Yue
language : en
Publisher: Springer Science & Business Media
Release Date : 2010-07-28
Proceedings Of The 20th International Conference On Fluidized Bed Combustion written by Guangxi Yue and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-07-28 with Science categories.
The proceedings of the 20th International Conference on Fluidized Bed Combustion (FBC) collect 9 plenary lectures and 175 peer-reviewed technical papers presented in the conference held in Xi'an China in May 18-21,2009. The conference was the 20th conference in a series, covering the latest fundamental research results, as well as the application experience from pilot plants, demonstrations and industrial units regarding to the FBC science and technology. It was co-hosted by Tsinghua University, Southeast University, Zhejiang University, China Electricity Council and Chinese Machinery Industry Federation. A particular feature of the proceedings is the balance between the papers submitted by experts from industry and the papers submitted by academic researchers, aiming to bring academic knowledge to application as well as to define new areas for research. The authors of the proceedings are the most active researchers, technology developers, experienced and representative facility operators and manufacturers. They presented the latest research results, state-of-the-art development and projects, and the useful experience. The proceedings are divided into following sections: • CFB Boiler Technology, Operation and Design • Fundamental Research on Fluidization and Fluidized Combustion • C02 Capture and Chemical Looping • Gasification • Modeling and Simulation on FBC Technology • Environments and Pollutant Control • Sustainable Fuels The proceedings can be served as idea references for researchers, engineers, academia and graduate students, plant operators, boiler manufacturers, component suppliers, and technical managers who work on FBC fundamental research, technology development and industrial application.
Powder Technology
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Author : Kōichi Iinoya
language : en
Publisher: Taylor & Francis Group
Release Date : 1984
Powder Technology written by Kōichi Iinoya and has been published by Taylor & Francis Group this book supported file pdf, txt, epub, kindle and other format this book has been release on 1984 with Particles categories.
Chemical Reactor Modeling
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Author : Hugo A. Jakobsen
language : en
Publisher: Springer Science & Business Media
Release Date : 2014-04-02
Chemical Reactor Modeling written by Hugo A. Jakobsen and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-04-02 with Technology & Engineering categories.
Chemical Reactor Modeling closes the gap between Chemical Reaction Engineering and Fluid Mechanics. The second edition consists of two volumes: Volume 1: Fundamentals. Volume 2: Chemical Engineering Applications In volume 1 most of the fundamental theory is presented. A few numerical model simulation application examples are given to elucidate the link between theory and applications. In volume 2 the chemical reactor equipment to be modeled are described. Several engineering models are introduced and discussed. A survey of the frequently used numerical methods, algorithms and schemes is provided. A few practical engineering applications of the modeling tools are presented and discussed. The working principles of several experimental techniques employed in order to get data for model validation are outlined. The monograph is based on lectures regularly taught in the fourth and fifth years graduate courses in transport phenomena and chemical reactor modeling and in a post graduate course in modern reactor modeling at the Norwegian University of Science and Technology, Department of Chemical Engineering, Trondheim, Norway. The objective of the book is to present the fundamentals of the single-fluid and multi-fluid models for the analysis of single and multiphase reactive flows in chemical reactors with a chemical reactor engineering rather than mathematical bias. Organized into 13 chapters, it combines theoretical aspects and practical applications and covers some of the recent research in several areas of chemical reactor engineering. This book contains a survey of the modern literature in the field of chemical reactor modeling.