Scale-up and Hydrodynamics of Fluidized Beds with Fractal-Like Injectors PDF Download

Author: Yi Cheng
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages :

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Author: Martin R Dis Li
Publisher: Sudwestdeutscher Verlag Fur Hochschulschriften AG
ISBN: 9783838133218
Category :
Languages : en
Pages : 372

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Rising gas bubbles in bubbling fluidized beds are important for all hydrodynamics related phenomena, e.g. mass transfer, gas bypassing, heat transfer, gas-solids mixing, etc. However, still many interactions of bubbles with specific operation conditions in fluidized beds are unknown. In this work, fluidized beds with vertical heat exchangers are investigated. Vertical heat exchangers are in this case used to remove the heat of reaction from the exothermal methanation reaction for the production of synthetic natural gas (SNG) from wood. Several vertical tube bank configurations varying in their diameter, tube-to-tube spacing, and arrangement (square vs. triangular) have been immersed into a lab-scale fluidized bed. By means of optical probing and pressure fluctuation measurements, their influence on the rising gas bubbles has been evaluated by means of statistical tools. Findings from these experiments are furthermore used to develop a modified approach to scale up fluidized beds with vertical internals.

Author: Michel Laurent Lapidus
Publisher: American Mathematical Soc.
ISBN: 0821836382
Category : Mathematics
Languages : en
Pages : 592

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This volume offers an excellent selection of cutting-edge articles about fractal geometry, covering the great breadth of mathematics and related areas touched by this subject. Included are rich survey articles and fine expository papers. The high-quality contributions to the volume by well-known researchers--including two articles by Mandelbrot--provide a solid cross-section of recent research representing the richness and variety of contemporary advances in and around fractal geometry. In demonstrating the vitality and diversity of the field, this book will motivate further investigation into the many open problems and inspire future research directions. It is suitable for graduate students and researchers interested in fractal geometry and its applications. This is a two-part volume. Part 1 covers analysis, number theory, and dynamical systems; Part 2, multifractals, probability and statistical mechanics, and applications.

Author: J.R. Grace
Publisher: Springer Science & Business Media
ISBN: 9400900953
Category : Science
Languages : en
Pages : 599

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Since the late 1970s there has been an explosion of industrial and academic interest in circulating fluidized beds. In part, the attention has arisen due to the environmental advantages associated with CFB (circulating . fluidized bed) combustion systems, the incorporation of riser reactors employing cir culating fluidized bed technology in petroleum refineries for fluid catalytic cracking and, to a lesser extent, the successes of CFB technology for calcina tion reactions and Fischer-Tropsch synthesis. In part, it was also the case that too much attention had been devoted to bubbling fluidized beds and it was time to move on to more complex and more advantageous regime,S of operation. Since 1980 a number of CFB processes have been commercialized. There have been five successful International Circulating Fluidized Bed Confer ences beginning in 1985, the most recent taking place in Beijing in May 1996. In addition, we have witnessed a host of other papers on CFB funda mentals and applications in journals and other archival publications. There have also been several review papers and books on specific CFB topics. However, there has been no comprehensive book reviewing the field and attempting to provide an overview of both fundamentals and applications. The purpose of this book is to fill this vacuum.

Author: Jacob Fish
Publisher: Oxford University Press
ISBN: 0199233853
Category : Mathematics
Languages : en
Pages : 631

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Small scale features and processes occurring at nanometer and femtosecond scales have a profound impact on what happens at a larger scale and over an extensive period of time. The primary objective of this volume is to reflect the state-of-the-art in multiscale mathematics, modeling, and simulations and to address the following barriers: What is the information that needs to be transferred from one model or scale to another and what physical principles must be satisfied during thetransfer of information? What are the optimal ways to achieve such transfer of information? How can variability of physical parameters at multiple scales be quantified and how can it be accounted for to ensure design robustness?The multiscale approaches in space and time presented in this volume are grouped into two main categories: information-passing and concurrent. In the concurrent approaches various scales are simultaneously resolved, whereas in the information-passing methods the fine scale is modeled and its gross response is infused into the continuum scale. The issue of reliability of multiscale modeling and simulation tools which focus on a hierarchy of multiscale models and an a posteriori model of errorestimation including uncertainty quantification, is discussed in several chapters. Component software that can be effectively combined to address a wide range of multiscale simulations is also described. Applications range from advanced materials to nanoelectromechanical systems (NEMS), biologicalsystems, and nanoporous catalysts where physical phenomena operates across 12 orders of magnitude in time scales and 10 orders of magnitude in spatial scales.This volume is a valuable reference book for scientists, engineers and graduate students practicing in traditional engineering and science disciplines as well as in emerging fields of nanotechnology, biotechnology, microelectronics and energy.

Author: Suneel Krishan Gupta
Publisher:
ISBN:
Category : Fluidization
Languages : en
Pages :

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Author: S. S. Zabrodsky
Publisher: MIT Press (MA)
ISBN: 9780262240079
Category : Science
Languages : en
Pages : 0

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Author: Gyorgy Szekely
Publisher: Elsevier
ISBN: 0128146826
Category : Technology & Engineering
Languages : en
Pages : 476

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Sustainable Nanoscale Engineering: From Materials Design to Chemical Processing presents the latest on the design of nanoscale materials and their applications in sustainable chemical production processes. The newest achievements of materials science, in particular nanomaterials, opened new opportunities for chemical engineers to design more efficient, safe, compact and environmentally benign processes. These materials include metal-organic frameworks, graphene, membranes, imprinted polymers, polymers of intrinsic microporosity, nanoparticles, and nanofilms, to name a few. Topics discussed include gas separation, CO2 sequestration, continuous processes, waste valorization, catalytic processes, bioengineering, pharmaceutical manufacturing, supercritical CO2 technology, sustainable energy, molecular imprinting, graphene, nature inspired chemical engineering, desalination, and more. - Describes new, efficient and environmentally accepted processes for nanomaterials design - Includes a large array of materials, such as metal-organic frameworks, graphene, imprinted polymers, and more - Explores the contribution of these materials in the development of sustainable chemical processes

Author:
Publisher:
ISBN:
Category : Ergodic theory
Languages : en
Pages : 600

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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A bench-scale, two-dimensional multi-compartmentalized fluidized reactor was designed and studies of hydrodynamic behavior of fluidization of struvite pellets were performed. Also size growth distribution tests were analyzed qualitatively. The study validated a previously-proposed theory, concerning the relationship between dynamic pressure drop and upflow velocity as well the experimental protocol to determine the minimum fluidization velocity. Findings indicated that the mixture of two-sized particles would behave rather independently of each other, before the bed expansion. It was suggested that bed height measurement could be another promising method to pinpoint minimum fluidization velocity as there is a sharp bed surface "waking episode" during the process of a packed bed being gradually fluidized. Bed expansion equations for the prediction of void fraction as a function of superficial upflow velocity or vice versa, have been established for 4 groups of monosize particles, as well as two mixtures of two-sized particles. The equation constants did not agree well with previously established ones. The two layers of segregated mixture bed had congruent linear relationships between the logarithmic void fraction and logarithmic upflow velocity. It was found that a mixture does not always go through segregation, but only when the size difference is large enough. Size growth distribution tests were performed under different hydrodynamic configurations as well as seeding conditions. Conclusions can be made that a bed with uniformly- distributed particle void fractions and higher mixing energy input (upflow velocity), normally has better performance of struvite growth in size.