Wall-Bed Heat Transfer Characteristics of Three-Phase Packed and Fluidized Bed

Kato, Yasuo; Kago, Tokihiro; Uchida, Keita; Morooka, Shigeharu

doi:10.1252/kakoronbunshu.6.579

Cited by 10 publications

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“…The heat transfer can take place between the bed and the wall or between the bed and the immersed surface. Bed-to-wall heat transfer has been studied by few researchers. − Heat transfer between the bed and the immersed surface is more widely used in industry and has been the subject of several studies in the literature. ,,− An important link between column hydrodynamics and the heat-transfer process has also been well established by literature studies. − Therefore, the design and operating variables that affect hydrodynamics will also influence the heat-transfer rate. These parameters can be divided into two main categories: (1) operational parameters; (2) geometric parameters.…”

Section: Effect Of Operating Variables On Heat Transfermentioning

confidence: 99%

Heat Transfer in a Slurry Bubble Column Reactor: A Critical Overview

Jhawar

Prakash

2011

Ind. Eng. Chem. Res.

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Studies of heat transfer in slurry bubble column reactors have been reviewed and observed differences analyzed based on available data. Heat transfer in these reactors is a strong function of some parameters and a weak function of others. The parameters significantly influencing heat transfer in these reactors are the superficial gas velocity, thermophysical properties of liquid and solid particles, and size and concentration of the particles. Moreover, the rate of change with a parameter is dependent on the operating flow regime, particle properties, and presence of internals. Of all of the parameters, the effect of the particles is more complex and inadequately understood because particles influence the flow regime transition and thermophysical and rheological properties of the suspension, which, in turn, affect the hydrodynamic behavior and associated heat-transfer characteristics. The effects of the column diameter and internals have been investigated by a limited number of studies. A comparison of available data shows that the effect of the column diameter on heat transfer diminishes above 0.3 m. This, however, requires confirmation from larger-diameter studies together with associated hydrodynamic studies and appropriate modeling. Literature correlations for the heat-transfer coefficient have been reviewed and their limitations and applicability discussed. Axial and radial variations of heat-transfer coefficients reported in literature studies require appropriate design considerations.

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Section: Effect Of Operating Variables On Heat Transfermentioning

confidence: 99%

Heat Transfer in a Slurry Bubble Column Reactor: A Critical Overview

Jhawar

Prakash

2011

Ind. Eng. Chem. Res.

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Heat transfer in three‐phase fluidized beds

Chiu

Ziegler

1983

AIChE Journal

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Wall-to-bed heat transfer coefficients in three-phase fluidized beds with glass beads and cylindrical 7-alumina particles were determined experimentally. In the present study, the relative increase in heat transfer coefficient was found equal to the relative decrease in liquid holdup in three-phase fluidized beds. Modified Stanton number has been correlated with modified Reynolds number. STms = Stm2 = C Rem2-O.3O5 Pr-2/3The above correlation can be useful in reactor design. Heat transfer in three-phase fluidized beds is hypothesized to encounter a wall resistance and bed resistance in series. * Nominal particle size.Actual particle Sie. 6, and d, based on actual particle size.

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Fundamentals of gas‐liquid‐solid fluidization

1985

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depend on the ability to accurately predict the fundamental properties of the system, specifically, the hydrodynamics, the mixing of individual phases, and the heat and mass transfer properties. Identification of the flow regimes under which the system operates is crucial to an understanding of both the variations of these properties and overall system performance. This timely, comprehensive review describes in a systematic manner the status of fundamental gas-liquid-solid fluidization behavior. This review also discusses the areas in which current knowledge is deficient and further research is needed. SCOPEGas-liquid-solid fluidization is defined as an operation in which a bed of solid particles is suspended in gas and liquid media due to the net drag force of the gas and/or liquid flowing opposite to the net gravitational force or buoyancy force on the particles. Such an operation generates considerable, intimate contact among the gas, liquid and solid particles in these systems and provides substantial advantages for applications in physical, chemical or biochemical processing involving gas, liquid and solid phases.Various modes are possible for gas-liquid-solid fluidized-bed operation. The gas-liquid-solid fluidized bed can be operated with a cocurrent or countercurrent flow of a gas and a liquid with gas as the continuous phase. It can also be operated with a cocurrent or countercurrent flow of a gas and a liquid with liquid as the continuous phase. The states of fluidization are altered when the fluidized bed is tapered, or an upper retaining grid or a draft tube is present in the bed.This review examines both the experimental and modeling studies of the fundamental characteristics of gas-liquid-solid fluidization. Specifically, a comprehensive review is made on the hydrodynamics, the mixing of individual phases, and the heat and mass transfer behavior of various modes and states of gas-liquid-solid fluidization. Industrial application of the gasliquid-solid fluidized bed is briefly described. CONCLUSIONS AND SIGNIFICANCEGas-liquid-solid fluidization became a subject for fundamental research only about two decades ago. Considerable progress has been made with respect to an understanding of the phenomena of gas-liquid-solid fluidization since then. This review summarizes and analyzes the available information in the literature on this subject.Gas-liquid-solid fluidization can be classified mainly into four modes of operation. These modes are: cocurrent three-phase fluidization with liquid as the continuous phase (Mode 1-a); cocurrent three-phase fluidization with gas as the continuous phase (Mode 1-b); Inverse three-phase fluidization (Mode IJ-a); and fluidization represented by a turbulent contact absorber (TCA) (Mode II-b). Modes II-a and 11-b are achieved with a countercurrent flow of gas and liquid. Due to the complex nature of three-phase fluidization, however, various methods are K Muroyama is on leave from the Department of Environmental Chemistry and Technology, Tottori University, Tottori, 680, Japa...

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Wall-Bed Heat Transfer Characteristics of Three-Phase Packed and Fluidized Bed

Cited by 10 publications

References 0 publications

Heat Transfer in a Slurry Bubble Column Reactor: A Critical Overview

Heat Transfer in a Slurry Bubble Column Reactor: A Critical Overview

Heat transfer in three‐phase fluidized beds

Fundamentals of gas‐liquid‐solid fluidization

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