Download or read book Fluid Dynamics in a Two Dimensional Fluidized Bed of Large Particles written by Adonis C. Stephanakis and published by . This book was released on 1980 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observation shows that bubbles in large particle fluidized beds behave quite differently from beds of fine particles. They expand and can grow faster than they rise. Bubbles in fine particle beds seem to grow primarily by coalescence, while in large particle beds they are observed to grow mainly without coalescence. The aim of this study was to gain a better insight into bubble behavior in fluidized beds of intermediate and large particles (particle diameter greater than 0.4 mm), and understand the cause of the observed bubble growth. In the theoretical part of this work it is shown that emulsion voidage invariability, incompressible viscous gas flow and potential solids flow assumed by existing theoretical two-phase models cannot account for the observed gas accumulation within bubbles. A simplified theoretical form for the gas accumulation rate in a cylindrical bubble is developed. It is based on different areas of gas inflow and outflow at the bubble boundary, and on the fact that the emulsion voidages above and below the bubble are different. It was shown that voidage variations in the emulsion phase around a bubble are important to bubble growth considerations. The experimental cases analyzed for single growing two dimensional bubbles indicate a higher voidage at the wake region, than the voidage at the nose of the bubble. It was found that a relatively small difference in emulsion voidage above and below the bubble can cause significant gas accumulation within the bubble reaching values comparable to the gas throughflow. Finally the movement of bubbles in the vicinity of an immersed tube and pressure-time curves representing the slow bubble and rapid bubble growth regime, and the transition range are analyzed in order to identify important bubble behavior characteristics. An experimental set up was developed making possible simultaneous permanent recording of the two-dimensional bubble behavior and instantaneous pressure data acquisition at multiple locations in an area under study. Lapsed cinematography and a special circuit activating the data acquisition system was used. The experimental set up enabled the collection of a large amount of data which gave valuable information about fluid dynamic behavior in the vicinity of an immersed tube. Experiments were performed at atmospheric pressure and room temperature in a two-dimensional fluidized bed with an immersed 50.8.mm (2 in) in diameter internal located at a height 0.35 m above the distributor plate. Glass, sand and dolomite particles with mean surface particle diameters of 0.65 to 2.6 mm were used. Superficial air velocities used spanned a region from well below minimum fluidization conditions to 2.82 m/s.
Download or read book Multiphase Flow and Fluidization written by Dimitri Gidaspow and published by Elsevier. This book was released on 2012-12-02 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Useful as a reference for engineers in industry and as an advanced level text for graduate engineering students, Multiphase Flow and Fluidization takes the reader beyond the theoretical to demonstrate how multiphase flow equations can be used to provide applied, practical, predictive solutions to industrial fluidization problems. Written to help advance progress in the emerging science of multiphase flow, this book begins with the development of the conservation laws and moves on through kinetic theory, clarifying many physical concepts (such as particulate viscosity and solids pressure) and introducing the new dependent variable--the volume fraction of the dispersed phase. Exercises at the end of each chapterare provided for further study and lead into applications not covered in the text itself. Treats fluidization as a branch of transport phenomena Demonstrates how to do transient, multidimensional simulation of multiphase processes The first book to apply kinetic theory to flow of particulates Is the only book to discuss numerical stability of multiphase equations and whether or not such equations are well-posed Explains the origin of bubbles and the concept of critical granular flow Presents clearly written exercises at the end of each chapter to facilitate understanding and further study
Download or read book Fluidization Engineering written by D. Kunii and published by Elsevier. This book was released on 2013-10-22 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluidization Engineering, Second Edition, expands on its original scope to encompass these new areas and introduces reactor models specifically for these contacting regimes. Completely revised and updated, it is essentially a new book. Its aim is to distill from the thousands of studies those particular developments that are pertinent for the engineer concerned with predictive methods, for the designer, and for the user and potential user of fluidized beds. Covers the recent advances in the field of fluidization. Presents the studies of developments necessary to the engineers, designers, and users of fluidized beds.
Download or read book Fluidized Bed Reactors Processes and Operating Conditions written by John G. Yates and published by Springer. This book was released on 2016-09-27 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fluidized-bed reactor is the centerpiece of industrial fluidization processes. This book focuses on the design and operation of fluidized beds in many different industrial processes, emphasizing the rationale for choosing fluidized beds for each particular process. The book starts with a brief history of fluidization from its inception in the 1940’s. The authors present both the fluid dynamics of gas-solid fluidized beds and the extensive experimental studies of operating systems and they set them in the context of operating processes that use fluid-bed reactors. Chemical engineering students and postdocs as well as practicing engineers will find great interest in this book.
Download or read book Essentials of Fluidization Technology written by John R. Grace and published by John Wiley & Sons. This book was released on 2020-06-15 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: A concise and clear treatment of the fundamentals of fluidization, with a view to its applications in the process and energy industries.
Download or read book Large Particle Fluidization a Photographic Study of a Two Dimensional Fluidized Bed written by Michael William Ferrell and published by . This book was released on 1978 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fast Fluidization written by and published by Academic Press. This book was released on 1994-12-23 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last decade, circulating fluidization or fast fluidization has developed rapidly, superseding standard bubbling fluidization in many applications; for example, fast fluidization provides a better means forcontrolling emissions from the combustion of high-sulfur fuels and excels when used in boilers in steam plant and power stations. China initiated the study of fast fluidization in the early 1970s. Focusing on the substantial research cultivated in that country, with Kwauk at the leading edge, this latest volume in the Advances in Chemical Engineering Series is written in the context of the international state of the art and addresses some of the most vital issues surrounding this fluidization method."
Download or read book Fluidization VIII written by Jean François Large and published by . This book was released on 1996 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bubbles Drops and Particles in Non Newtonian Fluids written by R.P. Chhabra and published by CRC Press. This book was released on 2006-07-25 with total page 801 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bubbles, Drops, and Particles in Non-Newtonian Fluids, Second Edition continues to provide thorough coverage of the scientific foundations and the latest advances in particle motion in non-Newtonian media. The book demonstrates how dynamic behavior of single particles can yield useful information for modeling transport processes in complex multipha
Download or read book Fluidization written by J. F. Davidson and published by CUP Archive. This book was released on 1978-04-20 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nonlinear Mechanics in the Fluidizaton of Beds of Spherical Particles written by Antonio Francisco Parentes Fortes and published by . This book was released on 1986 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gas Flow in Fluidized Beds of Large Particles written by Goran N. Jovanovic and published by . This book was released on 1979 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas mixing is studied in fluidized beds of large particles. The bed is 0. 483 m by 0. 127 m (19 in. by 5 in.) in cross section and has transparent plexiglass panels on the front and back. A tube matrix made of twenty-seven 50.8 mm (2 in.) diameter plexiglass cylinders fixed in an equitriangular pitch (with the pitch to diameter ratio equal to 2) is used to study the effects of tubes. Experiments are done in a bed with and without tube array. Sand and dolomite particles with mean particle diameter of 1.3 mm (0. 051 in.) to 4.0 mm (0. 157 in.) are used. Gas velocities are varied from minimum fluidization velocity to an excess velocity of 2.5 m/s. Two large particle fluidization regimes are described. The experimental evidence is presented in support of the existence of slow bubble and exploding bubble regimes. A semi-theoretical equation establishing the boundary between these two modes of fluidization is derived. A slow bubble regime is encountered in the bed in which the interstitital velocity of the gas exceeds the rising velocity of bubbles. Here the gas uses the bubble as a convenient shortcut on its way through the bed. The exploding bubble regime is reached at higher superficial gas velocities when the bubble growth rate is of the same magnitude as the bubble rise velocity. Large pressure drop oscillations, gross gas bypassing, defluidization of some of the particles and rapid bubble growth are characteristics of the exploding bubble regime. A new criterion is suggested for distinguishing between the fast and the slow bubble regimes. The criterion is derived as a relationship between two non-dimensional groups. The expansion of the bed of large particles with and without tube array is also studied. Theoretical equations are proposed for correlating relative bed voidage versus relative excess gas velocity. They are based on the two-phase theory and all are developed as a special case of one general equation. The equation derived for the slow bubble regime fits the experimental data of this study better than other existing correlations. The equation developed for the fast bubble regime compares favorably with literature data for fine particles. A special case of the general equation can be developed for stationary bubbles and for the slugging regime. It is found that there is little difference in expansion of beds with and without a tube array at low excess gas velocities. However, for higher excess gas velocities expansion is considerably greater for beds with a tube array. Exploding bubbles in a bed without tubes are responsible for this difference. The dispersion of tracer gas injected continuously through a line source above the distributor plate is determined for time-averaged concentration measurements. The tracer concentration at points within the bed is successfully predicted using a single-phase model with interstitial gas velocity (based on average bed voidage) as a characteristic fluidization velocity. The model is insensitive to axial dispersion and depends only on radial dispersion coefficients. The radial dispersion coefficient does not depend on either horizontal or vertical position in the bed and is a strong function of excess gas velocity. Considerable difference is found in tracer dispersion in beds with and without tube array. A new model, called the meandering flow model, is proposed for gas flow through fluidized beds of large particles. The concept of meandering flow is developed on the basis of actual physical movement of gas. The series of peaks observed in tracer concentration data records are explained by a bulk lateral movement of gas induced by large bubbles. A simple mathematical technique is suggested for the analysis of tracer data. As a result of the application of the meandering flow model the turbulent and meandering dispersion coefficients are defined. Meandering of fluid through the bed does not contribute to gas mixing, and consequently the meandering dispersion coefficient has to be subtracted from the overall radial dispersion coefficient. Only the turbulent dispersion should be used in the evaluation of the extent of gas mixing in fluidized beds of large particles, which contributes to gas phase combustion.
Download or read book Masters Theses in the Pure and Applied Sciences written by Wade Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volume were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 26 (thesis year 1981) a total of 11 ,048 theses titles from 24 Canadian and 21 8 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 26 reports theses submitted in 1981, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.
Download or read book Fluid Bed Technology in Materials Processing written by C. K. Gupta and published by CRC Press. This book was released on 1998-12-28 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid Bed Technology in Materials Processing comprehensively covers the various aspects of fluidization engineering and presents an elaborate examination of the applications in a multitude of materials processing techniques. This singular resource discusses: All the basic aspects of fluidization essential to understand and learn about various techniques The range of industrial applications Several examples in extraction and process metallurgy Fluidization in nuclear engineering and nuclear fuel cycle with numerous examples Innovative techniques and several advanced concepts of fluidization engineering, including use and applications in materials processing as well as environmental and bio-engineering Pros and cons of various fluidization equipment and specialty of their applications, including several examples Design aspects and modeling Topics related to distributors effects and flow regimes A separate chapter outlines the importance of fluidization engineering in high temperature processing, including an analysis of the fundamental concepts and applications of high temperature fluidized bed furnaces for several advanced materials processing techniques. Presenting information usually not available in a single source, Fluid Bed Technology in Materials Processing serves Fluidization engineers Practicing engineers in process metallurgy, mineral engineering, and chemical metallurgy Researchers in the field of chemical, metallurgical, nuclear, biological, environmental engineering Energy engineering professionals High temperature scientists and engineers Students and professionals who adopt modeling of fluidization in their venture for design and scale up
Download or read book Gas Fluidization written by M. Pell and published by Elsevier. This book was released on 2012-12-02 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a much-needed fluidization handbook for practising engineers. There are few plants which do not have a fluid bed process operating somewhere on the site, yet engineers rarely have any formal training in the subject. College courses often emphasize academic issues rather than industrial needs, and a study of the literature reveals an overwhelming abundance of correlations and experimental data.As this is a practical book, the author has minimized theoretical development of fundamental equations in favor of giving correlations which have been developed for large scale equipment. In some cases, where several correlations might apply, the author has chosen one or two which work best according to his own experience. Design procedures are described which should assist the designer and the operator of fluid beds to improve his process and to avoid some often-encountered pitfalls. The material will also be useful as a supplementary text to a course on fluidization, the emphasis on commercial design being a stimulating counterpoint to a strongly academic viewpoint.
Download or read book Circulating Fluidized Bed Boilers written by Prabir Basu and published by Springer. This book was released on 2015-04-07 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: · Explains operation and scientific fundamentals of circulating fluidized bed (CFB) boilers · Outlines practical issues in industrial use · Teaches how to optimize design for maximum reliability and efficiency · Discusses operating and maintenance issues and how to troubleshoot them This book provides practicing engineers and students with insight into the design and operation of circulating fluidized bed (CFB) boilers through a combination of theoretical concepts and practical experience. An emphasis on combustion, hydrodynamics, heat transfer, and material issues illustrates these concepts with numerous examples from actual operating plants. The relevance of design and feed-stock parameters to the operation of a CFB boiler are also examined, along with their impacts on designs of mechanical components, including cyclones, air distributor grids, and solid recycle systems. This versatile resource explains how fluidized bed equipment works and how the basic principles of thermodynamics and fluid mechanics influence design, while providing insight into planning new projects, troubleshooting existing equipment, and appreciating the capabilities and limitations of the process. From hydrodynamics to construction and maintenance, the author covers all of the essential information needed to understand, design, operate, and maintain a complete fluidized bed system. It is a must for clean coal technology as well as for biomass power generation.
Download or read book Fluid Dynamics of Turbulent Fluidized Beds for Geldart s Group B Particles written by Tom Wytrwat and published by Cuvillier Verlag. This book was released on 2022-02-15 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: An in-depth experimental study of the fluid dynamics of turbulent fluidized beds with particles of Geldart’s Group B was carried out. For this purpose, fluidization behavior was investigated in different fluidized bed plants having diameters in the range of 0.05 m to 1 m. Pressure fluctuation analysis has been used as an identification tool for the turbulent fluidized bed regime. Different fluidization conditions have been investigated by variation of the fluidized bed properties, the bed material properties, and the gas properties. Based on the measured data, a correlation predicting the transition velocity from bubbling to turbulent fluidization is introduced. To investigate the local flow structure, capacitance probe measurements have been carried out. Using this measurement technique, local solids concentrations and properties of rising bubbles have been determined and analyzed. Finally, an empiric fluid dynamic model was developed using the local measurement data. It is mainly based on capacitance probe measurements and shows high accuracy in comparison to pressure data.
