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Bubble-Free Fluidization Of Particles In The Voids Of A Packing Of Coarse Spheres, Bruno Formisani, Rossella Girimonte, Patrizia Bafaro, Vincenzino Vivacqua

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Confining a bed of relatively fine particles in a packing of coarse spheres prevents the onset of bubbly flow past their point of incipient fluidization. To improve present representations of confined fluidization, experiments on several cuts of solids of various density are analysed and interpreted by adapting some fundamental relationships of the fluidization theory to the peculiar geometry provided by the confining environment.

Motion Of A Large Object In A 2d Bubbling Fluidized Bed, Antonio Soria-Verdugo, L. M. García-Gutiérrez, S. Sanchez-Delgado, U. Ruiz-Rivas

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

The motion of a large object in a bubbling fluidized bed is experimentally studied using digital image analysis. A wide range of fluidized bed applications involves the motion of large objects within the bed, such objects being reactants, catalysts, agglomerates, etc.

The experiments were run in a 2D bubbling fluidized bed with glass spheres as bed material. The object motion is measured using tracking techniques, while independent measurements of the dense phase velocity (using PIV) and bubble velocity were carried out. The effect of the excess gas velocity on the object motion was also analyzed.

It is generally accepted that …

Particle Clusters In Fluidized Beds, Ray Cocco, Frank Shaffer, S.B. Reddy Karri, Roy Hays, Ted Knowlton

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Accurately predicting the entrainment rate is important in designing a commercial fluidized bed. However, most correlations fall short in providing an accurate prediction of the entrainment rate. Many correlations assume that smaller particles have a higher entrainment rate than larger particles; but, this is often not the case. Smaller particles can, and often do, have lower effective entrainment rates than larger particles. This has been presumed from several different experiments. In one case, the entrainment rate of FCC catalyst fines was measured at different fluidized bed heights and found that higher entrainment fluxes were observed at lower bed heights (i.e., …

Investigation Of The Shifting-Parameter As A Function Of Particle Size Distribution In A Fluidized Bed Traversing From A Fixed To Fluidized Bed, Christo Rautenbach, M.C. Melaaen, B.M. Halvorsen

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Accurate predictions of pressure drops in fluidized beds are of great importance in the industry. Up to date no satisfactory correlation exists to predict the pressure drop in a fluidized bed as the bed is traversing from one regime to another. In the present study the powered addition correlation [1] is investigated for this particular application. It has been found that this correlation is well suited for the investigated application.

Table Of Contents, Sang Done Kim, Yong Kang, Jea Keun Lee, Yong Chil Seo

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

No abstract provided.

Multiple Orifice Bubble Generation In Gas-Solid Fluidized Beds: The Activation Region Approach, Sergio Sanchez Delgado, J.V. Briongos, A. Acosta-Iborra, D. Santana

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

This work addresses the bubble generation mechanism at multi-orifice distributors in gas-solid fluidized beds (FB). Different measurements techniques such as high speed video camera and Kistler pressure transducers were applied to obtain information from both local, and global bed dynamics. Pressure fluctuation time series are used for dynamic diagnosis of the 2-D facility used during the study. The bed was operated with different distributor plates at several bubbling conditions leading to different bubble flow patterns characterized by digital image analysis of both the dense and the bubble phases.

In order to explain the bubble pattern developed within the bed and …

Mixing Behavior And Hydrodynamic Study Of Gassolid-Solid Fluidization System: Co-Fluidization Of Fcc And Coarse Particles, Zeeshan Nawaz, Yujian Sun, Yue Chu, Fei Wei

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Gas-solid-solid (GSS) fluidization system is a unique piece of equipment and its features related to better mixing quality. The mixing and hydrodynamic behavior of FCC particles with coarse particles is investigated in 2D and 3D cofluidized beds. The reason of enhancing mixing and fluidization properties by adding coarse particles is particularly due to the movement of coarse particles, those breaks the strong interparticle forces between FCC particles and destroy bubble wake (bubble disassociation strategy), time to time. The attrition mass was measured by using Zeeshan relationship at designated conditions.

Gas And Solid Mixing In A Three Partitioned Fluidized Bed, Gyoung Tae Jin, Seung-Yong Lee, Young-Ju Seo, Solim Kang, Ho-Jung Ryu

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

There are many gas-solid reaction systems which take place simultaneously in a single reactor, such as coal gasification. By splitting the reactions, high concentrated gases can be obtained without separation processes. Dual fluidized bed was proposed for this purpose. Similarly, simultaneous adsorption/desorption systems with dry sorbent for CO2 capture and the gasification reaction system with a char combustor and a gasifier separately were developed.

For improving gas and solid mixing efficiencies of the dual fluidized beds, a hitherto unknown partitioned fluidized bed (PFB) is proposed. A basic concept of PFB is that lower parts between two separated fluidized beds are …

Prediction And Validation Of Effect Of Bed Length On Rtd Of Coal In A Bubbling Fluidized Bed, Zhihong Liu, Masahiro Narukawa, Makoto Takafuji, Toshiyuki Suda

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

The residence time distribution (RTD) of coal particles in a bubbling fluidized bed with continuous feeding is calculated with an extended convection-dispersion model, in which segregation of coal is accounted for. The effect of bed length on the RTD of coal is investigated, and the results are validated by experiments.

Conference Program, Sang Done Kim, Yong Kang, Jea Keun Lee, Yong Chil Seo

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Fluidization XIII: New Paradigm in Fluidization Engineering May 16-21, 2010 Hotel Hyundai, Gyeong-ju, Korea

Understanding Capture Efficiency In Fluidized Beds, K Seng Lim, Trevor D. Hadley, Jonian Nikolov

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

This paper describes an experimental study on the extent of capture efficiency in a fluidized bed system under controlled conditions. Using aerosols as tracer compound, the capture efficiency in a fluidized bed was quantitatively measured as a function of contact distance (time). The paper presents the experimental technique as well as the results relating the capture efficiency to the bed hydrodynamic. A theoretical model was developed to describe the influence of operating variables on the overall capture efficiency. Dominant mechanisms enabling the capture of the fine aerosols are elucidated.

Dynamic Elutriation Measurement In A Continuously Operated Bubbling Fluidized Bed, Willie Nicol, E. Du Toit, W. De Vos

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Measurements were performed using a novel thermal mass flow meter. The dynamic behaviour of the total elutriation rate was monitored from start-up until a steady rate was achieved. It was found that the elutriation rate at unsteady conditions can be as much as 5 times that of the steady value and that it can take more than an hour to reach steady state. This is attributed to the dynamic changes of the fines distribution between the fluidized bed and dipleg. It was further shown that a steady dipleg height does not indicate steady elutriation rates. Using the flow meter to …

Agglomeration During Fluidized-Bed Combustion Of Biomass, Li Shiyuan, Lu Qinggang, Teng Haipeng

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Wheat stalk is tested to investigate the formation of bed agglomeration. The results show that defluidization time decreases with the combustion temperature increasing. The minimum fluidization velocity of the bed material after the test increases. The K, Ca and Si elements play the most important role in bed defluidization.

Numerical Investigation Of Gas Sampling From Fluidized Beds, John Grace, Tingwen Li, Yongmin Zhang, Xiaotao Bi

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Gas mixing in a tall narrow fluidized bed operated in the slugging fluidization regime is studied with the aid of computational fluid dynamics. Three-dimensional numerical simulations are performed with an Eulerian-Eulerian model. Predicted axial and radial tracer concentration profiles for various operating conditions are generally in good agreement with experimental data from the literature. Different field variables including voidage, tracer concentration, and gas velocity at upstream and downstream levels are analysed to study gas mixing. Mean tracer concentrations in the dense phase and the bubble phase are evaluated and significant differences between them are found. The time-mean concentration is weighted …

Fibre-Optic Probe For The Simultaneous Measurement Of Gaseous Species Composition And Solids Volume Fraction, Jamal Chaouki, Jean-Philippe Laviolette, Gregory S. Patience

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

A novel infrared fibre-optic probe was developed to measure quantitatively and simultaneously solids volume fraction (1-E) and gaseous species composition (Yi) in a gas/solid fluidized bed. The fibre-optic probe was used with a FT-IR spectrometer to perform real-time and in-situ measurements of absorbance in the fluidized bed. The effect of (1-E) and Yi on the absorbance spectra were additive and could be independently calibrated. To calibrate the probe, fuel mole fractions and (1-E) were varied between 1.8 - 10.1 mol% and 0 - 0.45, respectively. A proof of concept for a novel application in fluidized beds was completed: the fibre-optic …

Particle Breakage In The Cyclones Of Fluidized Bed Systems, Marvin Kramp, Anja Püttmann, Andreas Thon, Ernst-Ulrich Hartge, Joachim Werther

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

A breakage model is developed to predict the change in particle size distribution of brittle materials that undergo mechanical stress in gas cyclones. The breakage probability depends on the cyclone inlet gas velocity, solids load, particle size, and a material-specific constant. The model is validated with data from experiments on a laboratory gas cyclone with aluminum oxide and iron oxide. The results are applied to calculate the particle size distribution of a chemical looping combustion process with iron ore as oxygen carrier.

Fast X-Ray Tomography Of A Bubbling Fluidized, Robert Frank Mudde

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

This paper presents results of a train of bubbles moving through a fluidized bed imaged with an X-ray Tomographic Scanner. The scanner consists of three X-ray sources equipped with 2*30 CdWO4 detectors each. The fluidized bed has a diameter of 23cm and is filled with polystyrene particles (mean diameter 560μm). The bed is set at minimal fluidization and additional gas is released from a single capillary, forming a train of bubbles moving upwards through the bed. The scanner measures the shape, size and velocity of the bubbles passing the measuring plane. We present data showing that the scanner can quantify …

List Of Reviewers, Sang Done Kim

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

List of reviewers for this publication.

An Electrical Capacitance Tomography Study Of Pressurized Fluidized Beds, Niels G. Deen, Willem Godlieb, Sander Gorter, J.A.M. Kuipers

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

Simultaneous electrical capacitance tomography measurements for two planes were performed to obtain detailed information on bubble characteristics in a pressurized fluidized bed. Average permittivity values were used to get estimates of bubble sizes, while cross correlation was applied to the signals of both planes to obtain average bubble rise velocities.

At low pressures, a wide variation in bubble size was observed. Large stable bubbles tend to affect fluidization smoothness significantly. At higher pressure, bubbles possessed a more uniform size and were in general smaller. Consequently fluidization behavior was observed to be smoother at higher pressures.

Digital Image Analyis Of Bubble Flow Distribution – Influence Of Operational Parameters, Johanna Olsson, David Pallarès, Filip Johnsson

The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering

In a first step towards investigating the horizontal fuel mixing in fluidized bed (FB) boilers, this work applies digital image analysis to study the bubble flow properties in a 2-dimensional FB unit. The work investigates the influence of fluidization velocity, bed height and gas-distributor pressure drop on the volume fraction and horizontal distribution of bubbles.