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Book Study of Gas solid Slugging Fluidized Bed with Geldart D Particles Using Hightemperature Electrical Capacitance Volume Tomography

Download or read book Study of Gas solid Slugging Fluidized Bed with Geldart D Particles Using Hightemperature Electrical Capacitance Volume Tomography written by Mingyuan Xu and published by . This book was released on 2017 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: Work in this thesis is focused on studying the slugging phenomenon at different temperatures in the fluidized bed test unit with Geldart D chemical looping oxygen carrier particles as the fluidized solid and air as the fluidizing gas. It not only serves to evaluate the performance of ECVT at high temperatures, but also to examine the effect of temperature on slugging fluidized bed behaviors. Little research has been published on this topic due to the difficulty of fluidized bed characterizations at high temperatures. The experiments were conducted at temperatures ranging from 25 °C to above 700 °C. The results show that slug rise velocity and frequency increase as gas velocity increases, which is consistent with literature data and theory. The results also show that the effect of temperature on the correlation between gas velocity and slug properties is minimal. In addition, a preliminary test for solids circulation rate measurement is conducted in the test unit to explore the proposed application of ECVT in chemical looping. Future plans for the test unit and continuing research on the slugging behavior are also proposed.

Book Gas Liquid Solid Fluidization Engineering

Download or read book Gas Liquid Solid Fluidization Engineering written by Liang-Shih Fan and published by Butterworth-Heinemann. This book was released on 2013-10-22 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive mechanistic interpretation of the transport phenomena involved in various basic modes of gas-liquid-solid fluidization. These modes include, for example, those for three-phase fluidized beds, slurry columns, turbulent contact absorbers, and three-phase fluidized beds, slurry columns, turbulent contact absorbers, and three-phase transport. It summarizes the empirical correlations useful for predicting transport properties for each mode of of operation.Gas-Liquid-Solid Fluidization Engineering provides a comprehensive account of the state-of-the-art applications of the three-phase fluidization systems that are important in both small-and large-scale operations. These applications include fermentation,biological wastewater treatment, flue gas desulfurization and particulates removal, and resid hydrotreating. This book highlights the industrial implications of these applications. In addition, it discusses information gaps and future directions forresearch in this field.

Book Transient 3 dimensional Behavior of Gas solid Fluidization Measured Using Electrical Capacitance Volume Tomography ECVT

Download or read book Transient 3 dimensional Behavior of Gas solid Fluidization Measured Using Electrical Capacitance Volume Tomography ECVT written by Bing Du and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Hydrodynamics of a Gas solid Fluidized Bed at High Temperature in the Presence of Interparticles Forces

Download or read book Hydrodynamics of a Gas solid Fluidized Bed at High Temperature in the Presence of Interparticles Forces written by Jaber Shabanian and published by . This book was released on 2015 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to a lack of proper measurement techniques at elevated temperatures, we approached this study by dividing it into two parts. The first part was aimed at exploring the fluidization behavior of a gas-solid fluidized bed at different levels of IPFs from global and local points of view. The second part focused on the hydrodynamic characterization of a gas-solid fluidized bed at high temperature while different levels of IPFs were deliberately introduced into a bed of otherwise fresh coarse particles. (Abstract shortened by ProQuest.).

Book Principles of Gas Solid Flows

Download or read book Principles of Gas Solid Flows written by Liang-Shih Fan and published by Cambridge University Press. This book was released on 1998-01-13 with total page 579 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discusses fundamental principles of gas-solid flows and their applications, and includes numerous examples and homework problems.

Book Theory and Simulation of Incipient Instability in Gas solid Fluidization

Download or read book Theory and Simulation of Incipient Instability in Gas solid Fluidization written by Kar Yang Look and published by . This book was released on 2006 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanism of incipient in gas-solid fluidized bed was investigated by using Computational Fluid Dynamics (CFD) simulation - FLUENT version 6.1.18. The Finite Volume Method (FVM) is employed to simulate the complex flow behaviours and heterogenous structure of the gas-solid fluidized bed. Fluidization of Geldart group A B and C particles were simulated. The formation and development of the plumes during incipient fluidization were studied. Different fluidization behaviours of Geldart group A, B and C particles were observed from the contours of gas volume fraction and velocity vector. The observation agreed well with characteristics and behaviours of particles in gas-solid fluidized bed as reported by Geldart (1973). A theory of transient instability adopted with the principles advanced by Tan and Thorpe (1992 and 1996) was proposed to calculate the theoretical transient Rayleigh number (Rac) for the onset of incipient instability. The mobilization of the particles occured once a critical value of transient Rayleigh number was exceeded. Different type of particles exhibit different Rac values. However, the Rac is almost independent of the superficial velocity. The incipient instability of gas-solid fluidized bed was first indentified when the initial stable air diffusion became distorted and particles began to move chaotically. The fluidization parameters such as gas volume fraction, bubble rise velocity and bed pressure drop were used to determine the critical time for onset of incipient instability. The simulated critical onset time (tc) and transient Rayleigh Number (Rac) for the incipient instability of gas-solid fluidized bed were then investigated. A correlation between Rac and permeability was derived, which provides a convenient and simple way to estimate the Rac. The predicted values of Rac were found to agree fairly with the literature data.

Book Fluidized Bed Reactors Processes and Operating Conditions

Download or read book Fluidized Bed Reactors Processes and Operating Conditions written by John G. Yates and published by Springer. This book was released on 2016-09-27 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fluidized-bed reactor is the centerpiece of industrial fluidization processes. This book focuses on the design and operation of fluidized beds in many different industrial processes, emphasizing the rationale for choosing fluidized beds for each particular process. The book starts with a brief history of fluidization from its inception in the 1940’s. The authors present both the fluid dynamics of gas-solid fluidized beds and the extensive experimental studies of operating systems and they set them in the context of operating processes that use fluid-bed reactors. Chemical engineering students and postdocs as well as practicing engineers will find great interest in this book.

Book Gas Fluidization Technology

Download or read book Gas Fluidization Technology written by D. Geldart and published by . This book was released on 1993 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Gas solid Fluidization

Download or read book Gas solid Fluidization written by Fei Wang and published by . This book was released on 2010 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas-solid fluidization in the mini- and micro-channels is examined experimentally using FCC particles in six mini- and micro-channels with sizes ranging from 700 um to 5 mm. The data conduced from a visualization system reveal a significant increase in the minimum fluidization and bubbling velocities as well as the wall friction in the mini- and micro-channels. The pressure overshoot in the mini-channels in this study is between 30% - 70%. The round-nosed slug and the wall slug are observed in the mini- and micro-channels. The fluidization regimes in the channels are significantly different from that in large gas-solid fluidized beds as the criterion for conventional regime transition are not predictive for that in the mini- and micro-channels. Specifically, a bubbling/slugging fluidization - particulate fluidization phenomenon is observed at low superficial gas velocities in the 700 um and 1 mm channels.

Book Measurement of Particle Concentration and Collision Frequency in Gas solid Suspensions

Download or read book Measurement of Particle Concentration and Collision Frequency in Gas solid Suspensions written by D. Jeffrey Lischer and published by . This book was released on 1993 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Studies on the Stochastic Behavior of the Gas solid Fluidized Bed

Download or read book Studies on the Stochastic Behavior of the Gas solid Fluidized Bed written by Yee-Wei Huang and published by . This book was released on 1984 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Handbook of Fluidization and Fluid Particle Systems

Download or read book Handbook of Fluidization and Fluid Particle Systems written by Wen-Ching Yang and published by CRC Press. This book was released on 2003-03-19 with total page 876 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Book Gas Flow in Fluidized Beds of Large Particles

Download or read book Gas Flow in Fluidized Beds of Large Particles written by Goran N. Jovanovic and published by . This book was released on 1979 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas mixing is studied in fluidized beds of large particles. The bed is 0. 483 m by 0. 127 m (19 in. by 5 in.) in cross section and has transparent plexiglass panels on the front and back. A tube matrix made of twenty-seven 50.8 mm (2 in.) diameter plexiglass cylinders fixed in an equitriangular pitch (with the pitch to diameter ratio equal to 2) is used to study the effects of tubes. Experiments are done in a bed with and without tube array. Sand and dolomite particles with mean particle diameter of 1.3 mm (0. 051 in.) to 4.0 mm (0. 157 in.) are used. Gas velocities are varied from minimum fluidization velocity to an excess velocity of 2.5 m/s. Two large particle fluidization regimes are described. The experimental evidence is presented in support of the existence of slow bubble and exploding bubble regimes. A semi-theoretical equation establishing the boundary between these two modes of fluidization is derived. A slow bubble regime is encountered in the bed in which the interstitital velocity of the gas exceeds the rising velocity of bubbles. Here the gas uses the bubble as a convenient shortcut on its way through the bed. The exploding bubble regime is reached at higher superficial gas velocities when the bubble growth rate is of the same magnitude as the bubble rise velocity. Large pressure drop oscillations, gross gas bypassing, defluidization of some of the particles and rapid bubble growth are characteristics of the exploding bubble regime. A new criterion is suggested for distinguishing between the fast and the slow bubble regimes. The criterion is derived as a relationship between two non-dimensional groups. The expansion of the bed of large particles with and without tube array is also studied. Theoretical equations are proposed for correlating relative bed voidage versus relative excess gas velocity. They are based on the two-phase theory and all are developed as a special case of one general equation. The equation derived for the slow bubble regime fits the experimental data of this study better than other existing correlations. The equation developed for the fast bubble regime compares favorably with literature data for fine particles. A special case of the general equation can be developed for stationary bubbles and for the slugging regime. It is found that there is little difference in expansion of beds with and without a tube array at low excess gas velocities. However, for higher excess gas velocities expansion is considerably greater for beds with a tube array. Exploding bubbles in a bed without tubes are responsible for this difference. The dispersion of tracer gas injected continuously through a line source above the distributor plate is determined for time-averaged concentration measurements. The tracer concentration at points within the bed is successfully predicted using a single-phase model with interstitial gas velocity (based on average bed voidage) as a characteristic fluidization velocity. The model is insensitive to axial dispersion and depends only on radial dispersion coefficients. The radial dispersion coefficient does not depend on either horizontal or vertical position in the bed and is a strong function of excess gas velocity. Considerable difference is found in tracer dispersion in beds with and without tube array. A new model, called the meandering flow model, is proposed for gas flow through fluidized beds of large particles. The concept of meandering flow is developed on the basis of actual physical movement of gas. The series of peaks observed in tracer concentration data records are explained by a bulk lateral movement of gas induced by large bubbles. A simple mathematical technique is suggested for the analysis of tracer data. As a result of the application of the meandering flow model the turbulent and meandering dispersion coefficients are defined. Meandering of fluid through the bed does not contribute to gas mixing, and consequently the meandering dispersion coefficient has to be subtracted from the overall radial dispersion coefficient. Only the turbulent dispersion should be used in the evaluation of the extent of gas mixing in fluidized beds of large particles, which contributes to gas phase combustion.