Entrainment of fine particles from fluidized beds

by Ahmed Kabir

Written in English
Published: Pages: 57 Downloads: 47
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Subjects:

  • Fluidization -- Mathematical models.,
  • Particles.

Edition Notes

Statementby Ahmed Kabir.
The Physical Object
Paginationx, 57 leaves, bound :
Number of Pages57
ID Numbers
Open LibraryOL16540934M

1 exp(2 z)S = - - × × S d W c p m (3) Here S c is a material constant, d p denotes the particle diameter, and W m is the mass-based specific energy with which the particle is pressed against a plane. For z Weichert (11) gives the relation = + z k (2)/5 where k is a parameter that represents the distribution of defects on the particle surface. ISBN: OCLC Number: Description: xi, pages: illustrations ; 31 cm: Contents: 1: Bubbles. Measurement of local bubble propertied in a fluidized bed --On particulate phase motion around a void in a fluidized bed --Influence of the distributor design on bubble characteristics in large diameter gas fluidized beds --Size distribution of . Abstract. A comprehensive study of gas-solids flow behaviors was conducted in a novel multi-stage circulating fluidized bed (MCFB). Experiments were carried out in a cold model apparatus (a jetting fluidized bed, JFB, of m diameter and m tall, a riser of m diameter and 12 m tall) at different elevated pressure, solids circulation rates and gas : Wei Nie. The fluidized bed boilers have a wide capacity range- T/hr to over T/hr. Mechanism of Fluidised Bed Combustion When an evenly distributed air or gas is passed upward through a finely divided bed of solid particles such as sand supported on a fine mesh, the particles are undisturbed at low Size: KB.

Horizontal vibration system. A horizontal vibration system was used to study the bubbling behavior in the fine powder bed. Figure 1 shows a schematic diagram of the experimental setup, which consists of a glass tube (i.d.: 22 mm, o.d.: 25 mm, l = mm), a bottom plate (o.d.: 30 mm), a rectangular solid (w = 8 mm, d = 12 mm, h = 50 mm), piezoelectric vibrators, and a Cited by: 8. particles fluidized beds fig bubble particle fluidization bubbles reactor velocity transfer fluidized bed catalyst fluidized beds chem bubbling eng emulsion geldart temperature conversion feed freeboard distribution A fluidized bed is formed when a quantity of a solid particulate substance (usually present in a holding vessel) is placed under appropriate conditions to cause the solid/fluid mixture to behave as a is usually achieved by the introduction of pressurized fluid through the particulate medium. This results in the medium then having many properties and characteristics of normal . design distributors with low pressure drop operation. Fluidized beds suspend solid fuels on upward-blowing jets of air during the combustion process. The main characteristics of fluidized bed are pressure drop, fluid velocities, bubble size and bed height. Computational fluid dynamics (CFD) simulation is the method to study this Size: 1MB.

THE EFFECT OF VIBRATION ON BED VOIDAGE BEHAVIORS IN FLUIDIZED BEDS WITH LARGE PARTICLES H. Jin1*, J. Zhang2 and B. Zhang2 1School of Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Phone: () (10) , Fax: () (10) , Beijing , China. E-mail: [email protected] the Scale-up of Circulating Fluidized Beds,” Powder Technology, , (). 5. Alam, M. and C. M. Hrenya, “Inelastic Collapse in Simple Shear Flow of a Granular Medium,”. Expansion of a Fluidized Bed Non-bubbling Fluidization Bubbling Fluidization Entrainment Heat Transfer in Fluidized Beds Gas–Particle Heat Transfer Bed–Surface Heat Transfer CONTENTS viiFile Size: 6MB. Entrainment of Particles from Fluidized Beds of Fine Powders. The Effects of Aeration on the Gravity Flow of Particulate Mate- rials in Vertical Standpipes. Investigation of the Solid Flow Pat. tern in a Spouted Bed. Development of Reactivity Parameters for Characterization of Coal in Fluidized Bed Combustion. Modeling.

Entrainment of fine particles from fluidized beds by Ahmed Kabir Download PDF EPUB FB2

Abstract. The residence time of carbon particles in a fluidized bed is a major factor determining combustion efficiency. Particles carried out of the system incompletely burnt in the flue gases are in the size range to microns; the dispersion and entrainment of these fines forms the subject of this report.

A parametric study on various factors that influence the release of fine particles (considered as dust) from a fluidized bed of binary mixtures of coarse and fine particles is presented. Based on available experimental data, an empirical relationship is developed for the entrainment rate of coarse particles at the exit of gas-fluidized beds, including the effects of fine particles.

This work examines the entrainment of fluid cracking catalyst (FCC) particles from a large bubbling fluidized bed (BFB). An experimental setup consisting of a m-inner diameter (i.d.), m-high column, a high-efficiency Stairmand cyclone, a sampling valve and a movable conical top was designed and built to measure the entrainment mass rate as well as the size Cited by: 2.

A comprehensive correlation to predict the entrainment rate of coarse particles at the exit of dense fluidized beds is developed based on extensive available experimental data. The correlation successfully includes the effects of gas velocity, temperature, particle density, particle size distribution, column diameter and height.

To determine the influence of coarse particles on the entrainment characteristics of fine particles, Yang et al. investigated the entrainment characteristics of Geldart group C powder from solid mixtures (groups A and C) in a fluidized bed (with an inner diameter of 40 mm and a height of mm) equipped with two vibrators and an by: 3.

The qualitative effect of temperature on the particle entrainment rate has been measured in a gas fluidized bed ( m i.d., m height). The gas velocity (− m/s), the bed temperature (12− °C), the particle density (− kg/m3), and the particle size (− mm) were considered as experimental variables.

The particle entrainment rate increased after an Cited by: Hays, R., et al. Small Particles Cluster Formation in Fluidized Beds and its Effect on Entrainment. in Circulating Fluidized Bed IX. Hamburg, Germany: TuTech Innovation GmbH.

Freeman, R., Measuring the flow properties of consolidated, conditioned and aerated powders — A comparative study using a powder rheometer and a rotational shear cell. Depending on the process, the particles may be classified by a cyclone separator and separated from or returned to the bed, based upon particle cut size.

Vibratory fluidized beds are similar to stationary beds, but add a mechanical vibration to further excite the particles for increased entrainment. Transport or flash reactor (FR). Entrainment is a process which might occur in fluidized beds to carry particles over the bed by means of fluid flow.

Entrainment flux of particles has to be known for the design of an appropriate gas-solid Entrainment of fine particles from fluidized beds book such as cyclone or filter.

Furthermore, the entrain-ment of particles out of the bed is a disadvantage in fluidized bed. @article{osti_, title = {Gas fluidization technology}, author = {Geldart, D.}, abstractNote = {This book discusses the following topics: single particles, fixed and quiescent reds; characterization of fluidized powders; hydrodynamics of bubbling fluidized beds; solids mixing; particle entrainment and carryover; high velocity fluidized beds; solid-gas separation; fluid-bed Author: Geldart, D.

Abstract. The effects were determined of the mass ratio of Geldart C particles on the total amount of particles (M fine / M total =0–50 wt%), superficial gas velocity (U g =– m/s) and coarse particle size distribution (mono, binary, flat, and Gaussian type) on entrainment of Geldart C particles in a bubbling fluidized bed with binary particles (coarse particles: d p Cited by: 1.

Some features of the entrainment of fine polydisperse particles from a fluiidized bed. ” Proceedings of the 1st All-Union Conference on Heterogeneous Processes involving Solids in Fluidized Beds [in Russian], GNTK SSSR, Tsitovich, O.B. Some features of the entrainment of fine polydisperse particles from a fluiidized : O.

Tsitovich. An especially important point in the operation of fluidized beds composed of fine particles is a) feedwater temperature b) solids injection rate c) bubble size d).

fine particles on the coefficient of entrainment rate is minimal for weight fractions less than 25%. Ma et al.

[8] reported that the effect of Geldart C particles on the coefficient of entrainment rate is mini-mal in a binary mixture system if it is less than 15%.

Osberg and Charlesworth [9] stated that if the weight fraction of fine particles. Article. Published in Chemical Engineering Science.

— — — P. A rotating fluidized bed is a promising fluidization technique for handling of fine particles, classified into the Geldart׳s group-C. However, significant particle entrainment. A novel line total entrainment measurement deviceon- specifically for use in, bubbling fluidized beds with relatively low entrainment rates, was developed by De Vos and coworkers ().

The measurement device was based on the principles of a thermal mass flow meThe change in temperature of the ter. gas fluidization technology Download gas fluidization technology or read online books in PDF, EPUB, Tuebl, and Mobi Format. Click Download or Read Online button to get gas fluidization technology book now.

This site is like a library, Use search. An increasing number of applications rely on the use of gas-fluidized beds of small particles to enhance processes based on the mass/heat transfer between a gas and a solid. On the other hand, experimental studies have shown that application of high-intensity acoustic fields serves to further intensify fluid.

A fluidized bed reactor (FBR) is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions. In this type of reactor, a fluid (gas or liquid) is passed through a solid granular material (usually a catalyst possibly shaped as tiny spheres) at high enough speeds to suspend the solid and cause it to behave as though it were a fluid.

Following the dramatic increase, the entrainment flux then exhibited the classical batch exponential decay as the fines were elutriated from the fluidized bed.

Evidence suggests that fine particles in many materials may be clumping together - resulting in a reduced entrainment rate. The clumps appear to be formed in the fluidized bed and can be. Plot that shows the conditions for particle entrainment for different types of particles.

Fine grain size on left, coarse grain on right (of x-axis) The increments the velocity increases by on the y-axis goes up unevenly (gets larger as you go up) because it gets harder to move more flocculated silt, silt that is packed into larger rocks/ boulders.

developed for the accurate measurement of solids entrainment into jets in fluidized beds. Experimental setup. A fluidized bed with two compartments, shown in Figure 3, was used for the solids entrainment measurements.

The fluidized bed is constructed of polycarbonate, has a rectangular cross-section of m × m, and is m tall.

The bed is. Fluidization (or fluidisation) is a process similar to liquefaction whereby a granular material is converted from a static solid-like state to a dynamic fluid-like process occurs when a fluid (liquid or gas) is passed up through the granular a gas flow is introduced through the bottom of a bed of solid particles, it will move upwards through the bed via the.

Study of entrainment from a fluidized bed containing coke particles in the presence of free moisture. Authors: Saber Ayatollahi, Cedric Briens, Franco Berruti.

Status: Unpublished. Contributions: Saber Ayatollahi conducted all experimental work. Characterization of Fluidization Quality in Fluidized Beds of Wet Particles; Some methods such as the falling ball velocity or the detection of micro-agglomeration from the entrainment of fine particles, are unaffected by agglomerates and detect only the change in bed fluidity.

International Journal of Chemical Reactor Engineering Cited by:   Advantages of Fluidized Beds • The circulation of solids between two fluidized beds makes it possible to transport the vast quantities of heat produced or needed in large reactors. • Heat and mass transfer rates between gas and particles are high when compared with other modes of contacting.

circulating fine bed material played an important role in entrainment of coarse solids. A correlation of drag force by the solids was obtained in the bottom part. The entrainment from the bottom is considered to be decisive influence on carry over of coarse particles. virtues of the fluidized-bed reactor drove its competitors from the market.

Fluidization occurs when small solid particles are suspended in an upward-flowing stream of fluid, as shown in Figure R Figure R From Kunii and Levenspiel Fluidization Engineering, Melbourne, FL Robert E. Krieger Pub. File Size: KB.

"This book is the latest in the series entitled Cambridge Monographs on Mechanics, and it is certainly a worthwhile contribution to interpreting the dynamics of fluidized particles the book provides useful insight impressively clear and supplemented with many lucid figures."Cited by:.

recovery. Most of these models relate entrainment recovery to two parameters: the water recovery to concentrate, and the degree of entrainment, a classification factor to account for the degree of drainage of entrained particles with respect to the water in the pulp and froth phases of a Cited by: 1.During the Fluid Coking Process™ bitumen is sprayed into a fluidized bed of hot coke particles.

The bitumen undergoes thermal cracking and is converted into gasses, condensable vapors, and solid coke, which deposits on the coke particles. These vapors rise through the vessel and result in entrainment of coke particles. Wet fine coke particles from the freeboard region enter the Author: Saber Ayatollahi.EXPERIMENTAL STURY OF PARTICLES MIXING BEHAVIOR IN A MODIFIED INTERNALLY CIRCULATING FLUIDIZED BED 24 Lei Yang, J.

T. Padding, J. A. M. Kuipers TWO FLUID MODELLING OF 3D CYLINDRICAL FLUIDIZED BEDS USING KINETIC THEORY FOR ROUGH SPHERES Heat and mass transfer; 1 Zhengfu Luo, Guilin Zhang, Bo Zhang, Shulei Song, Bo Lv.