Bubble properties in large-particle fluidized beds

1987 ◽  
Vol 42 (3) ◽  
pp. 479-491 ◽  
Author(s):  
L.R. Glicksman ◽  
W.K. Lord ◽  
M. Sakagami
Keyword(s):  
Large Particle ◽  
Fluidized Beds ◽  
Bubble Properties

Heat Transfer in Large Particle Bubbling Fluidized Beds

1984 ◽  
Vol 106 (1) ◽  
pp. 85-90 ◽  
Author(s):  
R. L. Adams
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Residence Time ◽  
Large Particle ◽  
Fluidized Beds ◽  
Horizontal Tube ◽  
Two Dimensional ◽  
Phase Contact ◽  
Emulsion Phase ◽  
Bubble Phase

The potential use of fluidized bed combustion of coal as a means of meeting air quality standards with high-sulfur fuels has motivated the development of theoretical models of heat transfer in large particle gas fluidized beds. Models of the separate contributions of emulsion and bubble phase heat transfer have been developed by Adams and Welty [1] and Adams [2, 3, 4] and have been substantiated by experimental data for a horizontal tube immersed in a two-dimensional cold bed obtained by Catipovic [5, 6]. The consolidation of these models to predict local and overall time-average heat transfer to immersed surfaces requires information regarding emulsion phase residence time and bubble phase contact fraction for the particular geometry of interest. The analytical procedure to consolidate these models is outlined in the present work, then applied to the case of a horizontal tube immersed in a two-dimensional atmospheric pressure cold bed. Measurements of emulsion phase residence time and bubble phase contact fraction obtained by Catipovic [5] are used in the calculations for particle diameters ranging from 1.3 to 6 mm. The results agree favorably with experimental data and further substantiate the fundamental assumptions of the model.

Bubble properties in three-phase inverse fluidized beds with viscous liquid medium

2007 ◽  
Vol 46 (8) ◽  
pp. 736-741 ◽  
Author(s):  
Sung Mo Son ◽  
Suk Hwan Kang ◽  
Uk Yeong Kim ◽  
Yong Kang ◽  
Sang Done Kim
Keyword(s):  
Liquid Medium ◽  
Viscous Liquid ◽  
Fluidized Beds ◽  
Three Phase ◽  
Bubble Properties

scholarly journals Bubble Properties in Bubbling and Turbulent Fluidized Beds for Particles of Geldart’s Group B

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1098
Author(s):  
Tom Wytrwat ◽  
Mahdi Yazdanpanah ◽  
Stefan Heinrich
Keyword(s):  
Fluidized Beds ◽  
Pressure Fluctuations ◽  
Bubble Velocity ◽  
Turbulent Regime ◽  
Bubble Behavior ◽  
Low Velocity ◽  
Group B ◽  
Superficial Gas Velocity ◽  
Bubble Properties

Predicting bubble properties in fluidized beds is of high interest for reactor design and modeling. While bubble sizes and velocities for low velocity bubbling fluidized beds have been examined in several studies, there have been only few studies about bubble behavior at superficial gas velocities up into the turbulent regime. For this reason, we performed a thorough investigation of the size, shape and velocity of bubbles at superficial gas velocities ranging from 0.18 m/s up to 1.6 m/s. Capacitance probes were used for the determination of the bubble properties in three different fluidized bed facilities sized of 0.1 m, 0.4 m and 1 m in diameter. Particles belonging to Geldart’s group B (Sauter mean diameter: 188 µm, solid density: ρs = 2600 kg/m3) were used. Correlations for the determination of bubble phase holdup, vertical bubble length and bubble velocity are introduced in this work. The shape of bubbles was found to depend on superficial gas velocity. This implies that at large superficial gas velocities the horizontal size of a bubble must be much smaller in comparison to its vertical size. This leads to a decrease of pressure fluctuations, which is observed in the literature as a characteristic of transitioning into a turbulent regime.

scholarly journals Spatiotemporal measurement of bubble properties in free-bubbling fluidized beds.

1986 ◽  
Vol 19 (5) ◽  
pp. 425-430 ◽  
Author(s):  
HIROYUKI HATANO ◽  
IBRAHIM ABDEL HAMID KHATTAB ◽  
KYOKO NAKAMURA ◽  
MASARU ISHIDA
Keyword(s):  
Fluidized Beds ◽  
Bubble Properties

A gas convection model of heat transfer in large particle fluidized beds

AIChE Journal ◽  
1979 ◽  
Vol 25 (3) ◽  
pp. 395-405 ◽  
Author(s):  
Ronald L. Adams ◽  
James R. Welty
Keyword(s):  
Heat Transfer ◽  
Large Particle ◽  
Fluidized Beds ◽  
Convection Model

Hydrodynamic Studies on Zeolite Fluidized Beds

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Vassilis J Inglezakis ◽  
Marinos Stylianou ◽  
Maria Loizidou
Keyword(s):  
Large Particle ◽  
Fluidized Beds ◽  
Particle Sizes ◽  
Expanded Bed ◽  
Minimum Fluidization Velocity ◽  
Ergun Equation ◽  
Smooth Flow ◽  
Bed Height ◽  
New Correlation ◽  
Size Groups

The present study presents systematic experimental data on the fluidization of zeolite particles in water-solid fluidized beds. Four particle size groups, 90-180 ?m, 180-250 ?m, 250-315 ?m and 315-500 ?m and 22 different volumetric flow rates were used, corresponding to Rep of 0.012 to 1.452. All particle sizes showed smooth flow rate vs expanded bed height curves. As is proven, the Ergun equation is useful for determining the minimum fluidization velocity for the large particle sizes by using a fixed sphericity value of 0.354. For the fluidized bed regime (us>umf), the Ergun equation fails to represent the data as it results in fluctuating particle sphericity values, while the Richardson–Zaki model seems to correlate the data for the large particle sizes only. A new correlation is presented, connecting bed voidage to Rep for all particle sizes with an average relative error of 2.38±2.49% and the range is 0.02-9%.

Heat transfer and bubble properties in three-phase circulating fluidized beds

2001 ◽  
Vol 56 (21-22) ◽  
pp. 6107-6115 ◽  
Author(s):  
Yong Jun Cho ◽  
Sa Jung Kim ◽  
Seok Hee Nam ◽  
Yong Kang ◽  
Sang Done Kim
Keyword(s):  
Heat Transfer ◽  
Fluidized Beds ◽  
Circulating Fluidized Beds ◽  
Three Phase ◽  
Bubble Properties
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