3 edition of Solids mixing and circulation in gas fluidized beds found in the catalog.
Solids mixing and circulation in gas fluidized beds
Written in English
Thesis (Ph.D.) - Polytechnic institute of Brooklyn. Microfilm of typescript. Ann Arbor: University Microfilms, 1962. 1 reel. 35mm.
|The Physical Object|
|Number of Pages||120|
In this study, the effects of operating variables on solid circulation rate and gas leakage between two beds have been investigated in a cold mode two-interconnected fluidized bed system. Bubbling Fluidized Beds When talking about a fluidized bed, mostly one refers to a bubbling fluidized bed type as shown in Fig. C. Gas fluidized beds are characterized by the ‘bubbles’ which form at superficial gas velocities only slightly higher than that required to just fluidize the particles.
a fluidized bed is that a bed of solid particles adopts a fluid-like behavior when a gas injected from below flows through it. A fluidized bed is known to provide a good gas-solids contact together with relatively high rates of solids and gas mixing. These properties have made fluidized beds a competitive technology in a wide variety ofCited by: 5. Solid mixing dynamics is of vital important to the processing rate, achievable homogeneity and product quality in the related industries of granular material. In this paper, solid mixing behaviors within a baffle-type internally circulating fluidized bed (ICFB) are numerically investigated using a three-dimensional computational fluid dynamics-discrete element method (CFD-DEM), in which the Cited by:
Horio's Scaling law (AIChEJ ) was confirmed regarding the similitude of solid mixing and circulation by using ferrite coated sand tracer for magnetic separation and plastic tracer particles. Fluidization Engineering, Second Edition, expands on its original scope to encompass these new areas and introduces reactor models specifically for these contacting regimes. Completely revised and updated, it is essentially a new book. Its aim is to distill from the thousands of studies those particular developments that are pertinent for the engineer concerned with predictive methods, for the 5/5(2).
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Shareable Link. Use the link below to share a full-text version of this article with your friends and colleagues. Learn by: Books; Join AIChE; ; Article. Solids mixing and circulation in gas fluidized beds. Eliyahu Talmor.
Polytechnic Institute of Brooklyn, Brooklyn, New York. Search for more papers by this author. Robert F. Benenati. Polytechnic Institute of Brooklyn, Brooklyn, New by: A small quantity of fine particles is noted to drastically affect the gas and solids mixing behavior in the turbulent fluidized bed.
The axial and radial dispersion coefficients of gas and solids reach their maximum when the fines content is about 15%. The ECT measurements illustrate the effect of adding fines on the flow behavior in the by: The movement of solids associated with the rise of a single gas bubble in an incipiently fluidized bed has been determined.
The bulk volume, measured at the porosity of incipient fluidization, of tracer solid which is transported across the original interface between undyed glass spheres in the upper region and dyed glass spheres (tracer solid) in the lower region, is approximately 30% of the Cited by: Circulating Fluidized Bed Technology Adjacent fluidized beds can be designed such that there is a substantial and controlled flow of solids between the beds, but very little mixing of gas.
This concept can be used as the basis for an oil shale retorting system in which one bed is Cited by: 5. Many researchers who have studied the solids mixing mechanism in fluidized bed, believe that solids mixing in the particulate fluidization regime originates from the solids dispersion, while that in the bubbling and turbulent fluidization regimes is closely related to the bubbles and motion of the bubbles.
Until now, four mechanisms of solids mixing have been considered in bubbling and turbulent fluidization: (1) mixing by solids circulation, (2) mixing Cited by: Bubbles and voids are the main reason of solids circulation in the fluidized beds. Shape, size, and frequency of the bubbles influence the diffusivity of the solids.
The bubbles in a fluidized bed can be characterized by the excess superficial gas velocity and type of the by: Introduction Understanding of solids mixing in a gas-solid fluidized bed is an important component in the design of com- mercial fluidized beds.
Solids mixing studies combined with gas flow analysis and the reaction mechanism provide the basis for designing a commercial fluidized bed reactor, while feeding coal into a bed of several hundred square meters is an intricate and costly op- by: Axial mixing in bubbling fluidized beds can be characterized based on turnover time, as proposed by Geldart (), who correlated the overall mixing rate (R m) with four terms: bulk density of dense phase, fraction of bed solids moving upward, mean particle upward velocity, and bed cross-sectional area.
He also defined the turnover time as the time required for particles to travel through one circuit Cited by: 1. Keywords: Particle mixing, Gas-solid fluidization, Bubbling bed, Cold model 1. INTRODUCTION Mixing of particles is an important factor in fluidized bed combustors.
The horizontal mixing of fuel particles affects the performance of the beds. The mixing has a great influence on File Size: KB. An inviscid model is developed to describe gross solid circulation and gas backmixing in axisymmetric fluidized beds.
Two distinct cases are shown to arise: 1. interstitial gas moves upwards everywhere; and. interstitial gas circulates giving rise to Cited by: 1. An Initial Value Approach to the Counter-Current Backmixing Model of the Fluid Bed. , DOI: /bkch Hong Il Cho, Chan-Hwa Chung, Gui Young Han, Gui Ryong Ahn, Jong Su Kong.
Axial gas dispersion in a fluidized bed of polyethylene by: Gas Solid Mixing 1. GBH Enterprises, Ltd. Process Engineering Guide: GBHE-PEG-MIX Gas Solid Mixing Information contained in this publication or as otherwise supplied to Users is believed to be accurate and correct at time of going to press, and is given in good faith, but it is for the User to satisfy itself of the suitability of the information for its own particular purpose.
SOLIDS MIXING General considérations Mixing Indices Fluidized Bed Solids Mixing General results Segregation in fluidized beds PART 2.
In this article a novel circulating‐turbulent fluidized bed (C‐TFB) featured by high solids holdup and high gross solids circulation has been introduced and tested. The purpose of the new design was to integrate conventional circulating and turbulent fluidized beds into a unique high‐density fluidization system for more efficient gas Cited by: A new fluidized bed gasifier with increased gas–solid interaction combining two circulating fluidized bed reactors is proposed.
The aim of the design is to generate a nitrogen (N 2) free product. Circulating Fluidized Bed Technology II is a result of a series of science-related conferences in the s. The text contains various studies, facts, and discussions on fluidized beds.
The book begins by going through the rise and fall of circulating systems, specifically fluid Edition: 1. Circulating Fluidized Bed Technology II is a result of a series of science-related conferences in the s.
The text contains various studies, facts, and discussions on fluidized beds. The book begins by going through the rise and fall of circulating systems, specifically fluid dynamics. An available theoretical model for mixing index in gas‐solid fluidized bed has been analyzed for further modification and improvement.
Assumption of 50% bed material moving in the upward direction and rest 50% in the downward direction considered for the above model (the counter‐flow circulation model) has been analyzed for optimum : Abanti Sahoo, Subal Rana.
Abstract. 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 heat transfer; fluid-bed drying; fluid beds as chemical reactors; solids transfer in fluidized systems.Abstract: A new fluidized bed gasifier with increased gas–solid interaction combining two circulating fluidized bed reactors is proposed.
The aim of the design is to generate a nitrogen (N2) free product gas with low tars and fines content. Therefore the system is divided into an air/combustion and a fuel/gasification reactor. Two gas streams areCited by: minimised or eliminated. The design of the circulating bed simply consists of two fluid bed units connected two together via a riser and a downcomer fitted with a non-mechanical valve.
Various aspects such as solid circulation rate, gas mixing, solids mixing, and pressure component around the circulating ioop were studied.