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Book Investigation of Pressure Overshoot in Gas fluidized Beds

Download or read book Investigation of Pressure Overshoot in Gas fluidized Beds written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Particle Pressures in Fluidized Beds Final Report

Download or read book Particle Pressures in Fluidized Beds Final Report written by and published by . This book was released on 1996 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction), they impart to the bed. So rather than directly measure the particle pressure, the authors inferred the values of the elasticity from measurements of instability growth in liquid beds; the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined) and then working backwards to determine the unknown coefficients, including the elasticity.

Book The Effect of Particle Size on the Properties of Gas fluidized Beds

Download or read book The Effect of Particle Size on the Properties of Gas fluidized Beds written by K. S. Sutherland and published by . This book was released on 1964 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of a continuous method for determining changes in particle size and particle size distribution in fluid-bed systems has been studied experimentally. Differential pressure measurements were employed to study the effects of solid particle size on the behavior of gas-fluidized beds. The relevant bed properties are briefly described and a review given of previous work on the study of fluidized-bed quality. It is shown that, within certain limitations, measurements of bed quality can be used to indicate changes in particle size. Gas-bubble velocities, while increasing in proportion to the square root of bubble diameter, are also shown to be dependent on particle size, increasing as the particle size decreases.

Book Gas fluidized Bed Vibration an Experimental Study

Download or read book Gas fluidized Bed Vibration an Experimental Study written by James Francis Welch and published by . This book was released on 1973 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Fluid Dynamics of Turbulent Fluidized Beds for Geldart s Group B Particles

Download or read book Fluid Dynamics of Turbulent Fluidized Beds for Geldart s Group B Particles written by Tom Wytrwat and published by SPE-Schriftenreihe 20. This book was released on 2022-02-15 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: An in-depth experimental study of the fluid dynamics of turbulent fluidized beds with particles of Geldart's Group B was carried out. For this purpose, fluidization behavior was investigated in different fluidized bed plants having diameters in the range of 0.05 m to 1 m. Pressure fluctuation analysis has been used as an identification tool for the turbulent fluidized bed regime. Different fluidization conditions have been investigated by variation of the fluidized bed properties, the bed material properties, and the gas properties. Based on the measured data, a correlation predicting the transition velocity from bubbling to turbulent fluidization is introduced. To investigate the local flow structure, capacitance probe measurements have been carried out. Using this measurement technique, local solids concentrations and properties of rising bubbles have been determined and analyzed. Finally, an empiric fluid dynamic model was developed using the local measurement data. It is mainly based on capacitance probe measurements and shows high accuracy in comparison to pressure data.

Book Micro Fluidization

Download or read book Micro Fluidization written by Guangwen Xu and published by Elsevier. This book was released on 2023-05-20 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micro Fluidization: Fundamentals and Applications provides background and history on micro fluidized bed research and development, summarizes and analyzes the hydrodynamic characteristics of gas-solid micro fluidized beds, and delves into areas such as research results of delayed onsets of minimum, bubbling and slugging fluidization regimes, as well as of the advanced transitions to turbulent and fast fluidization regimes. Based on these results, the wall effects – the key mechanism resulting in the unique behavior of micro fluidization – are analyzed. Other sections discuss gas and solid mixing characteristics in terms of gas residence time distribution, gas backmixing, and solids mixing. Final sections focus on presentations of the so-called micro fluidized bed reaction analyzer (MFBRA) – a powerful tool for catalyst screening, process development, optimization of reaction parameters, studies of reaction mechanism and kinetics, among many other purposes. The book describes, in detail, the MFBRA's system design characteristics, analytic methodologies and various applications in thermochemical and catalytic reaction analysis. - Includes up-to-date information (all related research results and insights) on micro fluidized beds, including how they are comprehensively summarized and analyzed - Describes and explains the unique characteristics of micro fluidized beds - Covers the fundamental aspects and applications related to gas-solids, liquid-solids, and gas-liquid-solids micro fluidized beds - Provides up-to-date and potential applications of micro fluidized beds

Book Fluidization of Fine Powders

    Fluidization of Fine Powders

    Book Details:
  • Author : José Manuel Valverde Millán
  • Publisher : Springer Science & Business Media
  • Release : 2012-10-12
  • ISBN : 9400755872
  • Pages : 144 pages

Download or read book Fluidization of Fine Powders written by José Manuel Valverde Millán and published by Springer Science & Business Media. This book was released on 2012-10-12 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the rich phenomenology exhibited by fine powders when they are fluidized by a gas flow. Fine powder cohesiveness leads to poor flowability, clumping, difficulty in fluidizing, irregular avalanching behavior, etc. Despite all the inconveniences, fine powder processes pervade the chemical, pharmaceutical, agricultural and mining industries among others. The author in this book analyzes the mechanism by which interparticle adhesive forces are reduced by means of surface additives. Different techniques have been developed in the last years to assist fluidization by helping the gas flow to mobilize and break cohesive aggregates, which help to homogenize fluidization. As reviewed in this book, the use of these techniques may have a relevant impact on novel processes based on fluidized beds of fine powder and with relevant applications on leading edge technologies such as Atomic Layer Deposition on nanoparticles and CO2 capture by gas-fluidized beds of adsorbent powders. The study of fluidized beds has a marked interdisciplinary character. This book is thus intended for academic and industrial researchers in applied physics, mechanical, chemical, and environmental engineering, who are interested in the special characteristics of fine powders.

Book An Investigation of the Influence of Fines Distribution and High Temperature on the Fluidization Behaviour of Gas Fluidized Beds Linked with Rhelogical Studies

Download or read book An Investigation of the Influence of Fines Distribution and High Temperature on the Fluidization Behaviour of Gas Fluidized Beds Linked with Rhelogical Studies written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book An Experimental Study of a Vertical Tube Gas fluidized Bed

Download or read book An Experimental Study of a Vertical Tube Gas fluidized Bed written by Kevin Matthew Mandich and published by . This book was released on 2010 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this experimental work was to investigate methods of measuring important fluidization properties in a vertical, cold-flow, gas-fluidized bed to gain an understanding of the fluidization characteristics of the bed materials used. Quantities such as pressure drop across the bed, mean bed height, and minimum fluidization velocity were determined using non-invasive methods and were compared to fundamental fluidized bed theories to verify proper performance of the experiment. Granular temperature near the wall, a quantity of great interest in this system, was also determined using a non-invasive technique. An Acoustic Shot Noise probe, developed by Cody et al. (1996), was used to correlate the vibrational energy at the fluidized bed wall to the average particle velocity normal to this surface. By determining the mechanical transfer function of the confining tube, it was possible to obtain an estimate for the granular temperature near the wall by performing a spectral analysis of the wall acceleration time signal. Experimentally-determined values of pressure drop, mean bed height, and minimum fluidization velocity agreed well with the values predicted from theory. Average granular temperature values also agreed well with those obtained through similar means (Cody et al., 1996). The mean bed expansion ratio and average granular temperature results were compared with those obtained from a Computational Fluid Dynamics simulation (Didwania et al., to appear). Good agreement was observed between experiment and simulation, and special attention was given to the effects of changing key parameters in the model.

Book A Statistical Study of Local Wall Pressure Fluctuations in Gas Fluidized Columns

Download or read book A Statistical Study of Local Wall Pressure Fluctuations in Gas Fluidized Columns written by FREDERIC MELVIN SWINEHART and published by . This book was released on 1966 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Stability of Gas Fluidized Beds

Download or read book Stability of Gas Fluidized Beds written by Kevin Matthew Mandich and published by . This book was released on 2013 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applied mathematical techniques are employed to investigate the hydrodynamic stability of three gas-fluidized bed problems. The first considers an unbounded bed subjected to a uniform fluid-phase pressure drop. The dispersion relation is solved numerically to determine the stability characteristics as a function of the bed parameters. Analytic solutions are derived for the cases of purely transverse and purely longitudinal disturbances. Long-wavelength analyses performed on each reveal the relevant stability mechanisms. Several of these are novel mechanisms stemming from the extension of kinetic gas theory to rapid granular flows used to close the equations of motion. The linear stability analysis is then applied to two bounded problems: a cylindrically-bound vertical bed and a planar bed whose bounding walls are inclined from the vertical. The base states and linear stability analyses for both problems are solved numerically to determine the complex frequency. In the 3D vertical bed, no particle movement is allowed in the base state, while this restriction is relaxed for the 2D inclined bed to allow for the non-uniform solid-phase pressure distribution. It is found that the axisymmetric disturbance is dominant in the cylindrical bed. The dependence of its growth rate on the particle diameter and density matches previously-published tendencies for a gas-fluidized bed to exhibit bubbling at minimum fluidization as a function of these parameters. At low angles of inclination [theta], the eigenmodes of the inclined bed and their characteristics exhibit similar behavior to those of the cylindrical bed. Analytic solutions derived for the limiting cases of full slip at the walls for both beds explain these similarities. The dominant mode of the inclined bed at large [theta] exhibits an eigenmode whose time-evolution yields regions of drastic voidage adjacent to the top wall, matching the development and propagation of bubbles observed in experiment. Pressure time signals were obtained during experiments performed on lab-scale vertical and inclined beds. A Fourier analysis yielded dominant experimental frequencies, which were compared to those from the numerical methods. The frequencies as a function of fluidization velocity and [theta] show qualitatively similar behavior between the stability analysis and experimental observations.