Engineering Commons^™

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.

Prediction Of Catalyst Attrition In An Industrial Fluidized Bed Plant Based On Lab Scale Attrition Tests, Ernst-Ulrich Hartge, Stefan Heinrich, Joachim Werther, Anja Püttmann, Andreas Thon, Gegory Patience, Richard Bockrath

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

The concept that catalyst attrition in a fluidized bed process can be simulated based on the attrition characteristics of the catalyst determined on labscale is applied to DuPont’s large scale process of maleic anhydride production from n-butane using a vanadium phosphorus oxide (VPO) catalyst. In the present cooperation effort the performance data and design parameters of the large scale plant are supplied by the École Polytechnique de Montréal and DuPont. At Hamburg University of Technology the catalyst’s attrition characteristics were determined in labscale attrition tests. Furthermore the fate of the solids in the process was simulated. The results of the …

Geldart Group Indication From Powder Measurements With A Rotating Drum Instrument, Clive Davies, Emile S. Webster

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

Data have been collected with a GDR, for powders from each Geldart Group, over a rotation rates in the range 0-22 r.p.m.. Composite plots of avalanching frequency ,slumping rate and rotation rate, show that power spectral density for Groups D and B is qute different from that observed for Groups A and C.

The Transport Disengagement Height (Tdh) In A Bubbling Fluidized Bed (Bfb), Chian Chan, Jonathan P.K. Seville, Jan Baeyens

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

Bubbles bursting at the surface of a BFB project particles into the freeboard. Coarser particles fall back, the solids loading declines with height in the freeboard, and fines are ultimately carried over. The height of declining solids loading is the TDH, measured in this research by Positron Emission Particle Tracking, and modeled from a balance of forces on ejected particles. Model predictions and PEPT-data are in good agreement. Empirical equations overestimate the TDH.

Investigation Of The Effect Of Fluidization Time On Electrostatic Charge Generation In Gas-Solid Fluidized Beds, Amanda Giffin, Andrew Sowinski, Poupak Mehrani

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

This work focused on determining the effect of the fluidization time on particle charging. Charge equilibrium was reached on the bed particles after 60 minutes. The wall particle layer was built with negative and positive charges. Similar sized particles migrated to each region of the bed regardless of fluidization time.

Effects Of Particle Size And Fluidizing Velocity On The Charge Density Of Entrained Fines, Xiaotao T. Bi, John Grace, Kwang Seok Choi, Muammar Omar

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

A previously-developed Faraday cup fluidized bed unit was modified to facilitate the in-situ monitoring of the transient entrainment rate and net charge of entrained fine powders. This enabled the determination of the transient charge density as a function of particle size and residence time of entrained fine particles. The results showed that the charge density increased significantly with increasing size of entrained fines, but was not very sensitive to the residence time and the fluidizing gas velocity for the finest entrained particles at gas velocities of 0.24 and 0.36 m/s. At Ug=0.48 m/s, the charge density of larger particles increased …

Electricity Generation Characteristics Of An Anaerobic Fluidized Bed Microbial Fuel Cell, Qingjie Guo, Shuju Zhao, Xuyun Wang, Xuehai Yue, Liangyu Hou

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

Anaerobic fluidized bed microbial fuel cell (AFBMFC) was developed to investigate the effect of fluidization behaviors on the electrogenesis capacity. Waste water and active carbon were used as liquid and solid phase, respectively. The fuel cell was started up successfully using anaerobic activated sludge as inoculums. The power density is increased with increasing circular liquid velocity up to 450 mW·m-2. High COD remove rate reached 93% after five days operation. Meanwhile, the effects of cathode area on the electrogenesis capacity of AFB MFC were also investigated.

Hydrodynamic Characteristics Of Liquid-Solid Fluidization Of Binary Mixtures In Tapered Beds, Sankarshana Talapuru Dr, J S N Murthy, S Nandana, Phani Kiran S V G R, V Ramesh

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

The problems associated with fluidization in cylindrical beds like entrainment of particles, limitation of operating velocity could be overcome by adopting tapered beds. There have been no systematic studies reported on fluidization behavior of binary mixtures wherein the effect of size ratio is considered on the hydrodynamic characteristics of liquid-solid fluidization in tapered beds. In the present work, an attempt has been made to study the fluidization behavior and hydrodynamic characteristics of liquid-solid fluidization of binary mixtures of size ratios ranging from 1.2 to 5.13 using sand of different sizes in tapered beds of apex angles 50, 100 and 150. …

Impact Behaviour Of Particles With Liquid Films: Energy Dissipation And Sticking Criteria, Sergiy Antonyuk, Stefan Heinrich, Stefan Palzer

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

The normal impact of spherical particles (elastic glass, elastic-plastic Al2O3) and non-spherical dominantly plastic agglomerates of amorphous maltodextrin on a wall with a liquid layer was studied. The objective was to investigate the effects of thickness (0.1-1 mm) and viscosity of the liquid layer (1-250 mPas) as well as of the impact velocity (1-3.0 m/s) of the granule on the restitution coefficient. The restitution coefficient was measured by using a free-fall apparatus. In the presence of a liquid layer, the higher the viscosity and thickness of the liquid layer the more the energy dissipated during impact and the smaller the …

Spinning Straw Into Gold: Turning Academic Papers Into Commercial Fluidized Bed Reactor Solutions, Charles O. Bolthrunis, Michael Hagan, Waheed A. Mukaddam

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

This paper presents an example of academic work that has been applied in industry. A case is presented of a solution to a serious operational problem involving fluidization phenomena threatening to cause structural damage to an operating chemical reactor. The process used to analyze the problem and arrive at a probable cause and design solutions are presented.

A Study On Denitrification In A Fluidized Bed Bioreactor, L. Prasanna Lakshmi, Y. Pydi Setty, K. Vimala

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

The work involves experimental investigation on biological denitrification in a fluidized bed reactor under anaerobic conditions using the microorganism Pseudomonas Stutzeri and plastic beads as fluidizing medium. The influence of various parameters like pH, initial nitrate concentration, Carbon/Nitrogen ratio, hydraulic retention time on nitrate-nitrogen removal rate from synthetic effluent prepared at the laboratory were studied in detail. The optimum operating conditions of pH, initial nitrate concentration, Carbon/Nitrogen ratio and flow rate obtained are 7.0–7.5, 15 mg/l, 1.5–2.0 and 4.41 x 10-5 m3/s respectively.

Chemical-Looping Steam Methane Reforming For Hydrogen Production In A Circulating Fluidized Bed Reactor, Sang Done Kim, Kang Seok Go, Young Wook Jeon, Chu Sik Park

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

Two-step steam methane reforming for hydrogen production using a chemical looping system is proposed to improve the conventional processes. The reaction characteristics with iron oxides as an oxygen carrier was determined in a circulating fluidized bed reactor. From this system, high concentrated hydrogen can be continuously produced without any post treatment.

The Hot Gas Desulfurization In A Compact Two Beds System Integrated With Coal Gasification And Fisher-Tropsch System, Young Cheol Park, Sung-Ho Jo, Seung-Yong Lee, Chang-Keun Yi

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

The hot gas desulfurization (HGD) technique is one of the elemental technologies of syngas purification having both thermal efficiency and very low emissions. The HGD is a novel method to efficiently remove H2S and COS in the syngas with regenerable sorbents at high temperature and high pressure condition. We propose a compact hot gas desulfurization system by which its operability is improved in stabilizing pressure balances among units. The proposed compact two beds system has two bubbling beds, solid injection nozzle, solid conveying line, and riser. The compact desulfurization system was located between coal gasifier and Fisher-Tropsch (F-T) reactor to …

A Novel Construction Of A Low-Pressure-Drop Air Nozzle Working With A 535mwe Cfb Boiler, Pawel Mirek, Wojciech Nowak, Marcin Klajny, Janusz Jabłoński

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

In the paper a novel construction of a low-pressure drop air-nozzle has been presented. It was designed in order to substitute the arrowhead nozzle working until now with a 535MWe CFB boiler. In comparison to the arrowhead nozzle the new construction has a lower pressure-drop and geometry, which is an effective barrier for backflow of a solid. In the paper numerical simulations as well as experimental studies of a new air nozzle have been presented. Laboratory tests have been conducted on a 3D test-stand equipped with six full scale air nozzles.

Development Of A Continuous Nanoparticle Coating With Electrospraying, N. Ellis, J. Ruud Van Ommen, C.U. Yurteri

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

Coating of micron-sized particles (host particles) with nanoparticles can result in modifying the surface properties of host particles leading to various applications. This work presents a novel concept of combining the electrospraying of nanoparticles onto the charged particles entrained out of the fluidized bed for developing a continuous coating process. By controlling the processes to effectively charge and contact particles using electric forces, we are able to fine-tune the properties of the obtained nano-coated particles.

Experimental And Computational Study On The Bubble Behavior In A 3-D Fluidized Bed With A Vertical-Axis, Rotating Distributor, Antonio Acosta Iborra, F. Hernández-Jiménez, C. Sobrino, M. De Vega

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

This work presents experimental measurements in a three-dimensional fluidized bed equipped with a novel vertical-axis, rotating distributor, together with two-fluid (Eulerian-Eulerian) CFD simulation results. The influence of the distributor rotation on the behavior of the bubbles in the experiments and in the CFD results is compared and critically analyzed.

Hydrodynamics On Chemical Looping Combustion Using Multiphase Cfd With Kinetic Theory Of Granular Flow, Jonghwun Jung, Isaac K. Gamwo

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

The fundamental knowledge of multiphase reactive hydrodynamics of the gassolid flow is essential for the design, optimization, and operation of industrial reactors. The multiphase computational fluid dynamics (CFD) model with the kinetic theory of granular flow, MFIX, developed earlier at the National Energy Technology Laboratory have been adapted to describe a fuel reactor of chemical looping combustion (CLC) processes. To understand hydrodynamics the chemical kinetics and mass transfer in the fuel reactor have been developed, where the reduction reaction is the first order of methane gas and the oxygen in metal oxygen carriers transfer to gas phase. The fuel conversion …

A Novel Chemical Looping Combustion Process: Pressure Drop And Solid Circulation Rate Modelling, Ali Hoteit, Yazdanpanah Mohammad-Mahdi, Forret Ann, Delebarre Arnaud, Gauthier Thierry

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

Experimental results from a cold flow unit of a novel chemical looping combustion configuration are presented in this paper. The system employs a non-mechanical lvalve to control solid flow rate and uses loop-seals to minimize gas leakage. A model was developed to predict solid flow rate and pressure variation in different elements of the system. The developed model was able to well predict solid flow rate within an error range of 10% for a wide solid flux range of 70 – 150 kg/m².s. Sensibility of the solid flow rate was analyzed for different operating parameters by aid of the model. …