Modeling of Axial and Radial Flow in Circulating Fluidized Bed Risers PDF Download

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

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Author: Guangxi Yue
Publisher: Springer Science & Business Media
ISBN: 3642026826
Category : Science
Languages : en
Pages : 1186

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Book Description
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.

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

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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: 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: Fabrizio Scala
Publisher: Elsevier
ISBN: 0857098802
Category : Technology & Engineering
Languages : en
Pages : 1091

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Book Description
Fluidized bed (FB) combustion and gasification are advanced techniques for fuel flexible, high efficiency and low emission conversion. Fuels are combusted or gasified as a fluidized bed suspended by jets with sorbents that remove harmful emissions such as SOx. CO2 capture can also be incorporated. Fluidized bed technologies for near-zero emission combustion and gasification provides an overview of established FB technologies while also detailing recent developments in the field.Part one, an introductory section, reviews fluidization science and FB technologies and includes chapters on particle characterization and behaviour, properties of stationary and circulating fluidized beds, heat and mass transfer and attrition in FB combustion and gasification systems. Part two expands on this introduction to explore the fundamentals of FB combustion and gasification including the conversion of solid, liquid and gaseous fuels, pollutant emission and reactor design and scale up. Part three highlights recent advances in a variety of FB combustion and gasification technologies before part four moves on to focus on emerging CO2 capture technologies. Finally, part five explores other applications of FB technology including (FB) petroleum refining and chemical production.Fluidized bed technologies for near-zero emission combustion and gasification is a technical resource for power plant operators, industrial engineers working with fluidized bed combustion and gasification systems and researchers, scientists and academics in the field. - Examines the fundamentals of fluidized bed (FB) technologies, including the conversion of solid, liquid and gaseous fuels - Explores recent advances in a variety of technologies such as pressurized FB combustion, and the measurement, monitoring and control of FB combustion and gasification - Discusses emerging technologies and examines applications of FB in other processes

Author: Young-Il Lim
Publisher: MDPI
ISBN: 3039439332
Category : Technology & Engineering
Languages : en
Pages : 114

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In this Special Issue, one review paper highlights the necessity of multiscale CFD, coupling micro- and macro-scales, for exchanging information at the interface of the two scales. Four research papers investigate the hydrodynamics, heat transfer, and chemical reactions of various processes using Eulerian CFD modeling. CFD models are attractive for industrial applications. However, substantial efforts in physical modeling and numerical implementation are still required before their widespread implementation.

Author:
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages : 72

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

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