Modelling the Flow Structure of Circulating Fluidized Bed Risers PDF Download

Author: Gregory John Davies
Publisher:
ISBN:
Category : Fluidization
Languages : en
Pages : 396

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

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Book Description
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: Annapurna Devi Nambula
Publisher:
ISBN: 9783330048560
Category :
Languages : en
Pages : 76

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Author: Shihui Zhou
Publisher:
ISBN:
Category :
Languages : en
Pages : 226

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A new theoretical approach to the modelling of the upward flow of gas-particle suspensions is presented. In this, the proposed theory is used to predict suspension concentration, radial gas and solids velocities, axial gas and solids velocities. This thesis provides a general expression for slip velocity between gas and solids phases. The equivalence of pressure gradient with suspension concentration is demonstrated. The experimentally observed existence of core-annulus flow structure, a rapidly- rising dilute core surrounded by a slowly-falling denser annulus adjacent to the pipe walls, in vertical risers is predicted by the theory. Sodium chloride tracer impulse injection was used to measure the longitudinal solids mixing in circulating fluidized bed risers of internal diameter 0.152 and 0.305m at superficial gas velocity from 2.8 to 5.0 m/s for mean solids circulation flux from 5.0 to 80 kg/m2s. The measured solids mixing data were satisfactorily described by a simple one-dimensional dispersion model which permits residence time distribution curves to be calculated directly from a knowledge of operating conditions. The degree of longitudinal solids mixing in the riser is found to decrease with increase in riser diameter. The measurement of instantaneous local temperature fluctuation traces and mean thermal boundary layers was conducted with a special probe for various operating conditions. A mechanism, in which eddying particle cloud swarms and gas packets are pictured as the receptors of heat, and relatively steady conduction of heat and unsteady random transport of heat play the principal roles in the wall-to-suspension heat transfer, is proposed and is analyzed mathematically. Overall heat transfer coefficients were measured on 0.180 m long heat transfer section in two scale cold model circulating fluidized bed risers at several temperature differences for ... powder at superfical gas velocity from 1.96 to 5.66 m/s, and for solids circulation fluxes up to 118.54 kg/m2s. Average heat transfer coefficients increase with suspension concentration which ranged from 0 to 86.09 kg/m3, and decrease with heat transfer temperature difference, Tw - Tb, which ranged from 12 to 121.5 degrees C Heat transfer coefficients are found to increase with riser diameter.

Author: Li Lu
Publisher:
ISBN:
Category : Fluidized-bed furnaces
Languages : en
Pages : 340

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Author: Wen-Ching Yang
Publisher: CRC Press
ISBN: 0824748360
Category : Science
Languages : en
Pages : 873

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This reference details particle characterization, dynamics, manufacturing, handling, and processing for the employment of multiphase reactors, as well as procedures in reactor scale-up and design for applications in the chemical, mineral, petroleum, power, cement and pharmaceuticals industries. The authors discuss flow through fixed beds, elutriation and entrainment, gas distributor and plenum design in fluidized beds, effect of internal tubes and baffles, general approaches to reactor design, applications for gasifiers and combustors, dilute phase pneumatic conveying, and applications for chemical production and processing. This is a valuable guide for chemists and engineers to use in their day-to-day work.

Author: Christoph Rudnick
Publisher:
ISBN: 9783826528941
Category :
Languages : en
Pages : 161

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Author: Pannala, Sreekanth
Publisher: IGI Global
ISBN: 1615206523
Category : Computers
Languages : en
Pages : 500

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"This book provides various approaches to computational gas-solids flow and will aid the researchers, graduate students and practicing engineers in this rapidly expanding area"--Provided by publisher.

Author:
Publisher: Elsevier
ISBN: 0444639705
Category : Technology & Engineering
Languages : en
Pages : 3064

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Book Description
27th European Symposium on Computer Aided Process Engineering, Volume 40 contains the papers presented at the 27th European Society of Computer-Aided Process Engineering (ESCAPE) event held in Barcelona, October 1-5, 2017. It is a valuable resource for chemical engineers, chemical process engineers, researchers in industry and academia, students, and consultants for chemical industries. - Presents findings and discussions from the 27th European Society of Computer-Aided Process Engineering (ESCAPE) event

Author: Haiying Qi
Publisher: Springer Science & Business Media
ISBN: 3642304451
Category : Technology & Engineering
Languages : en
Pages : 1306

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Book Description
Cleaner Combustion and Sustainable World is the proceedings of the 7th International Symposium on Coal Combustion which has a significant international influence. It concerns basic research on coal combustion and clean utilization, techniques and equipments of pulverized coal combustion, techniques and equipments of fluidized bed combustion, basic research and techniques of emission control, basic research and application techniques of carbon capture and storage (CCS), etc. Professor Haiying Qi and Bo Zhao both work at the Tsinghua University, China