Wall-to-Bed Mass Transfer in a Three-Phase Fluidized Bed with Twisted Tape as Internal

2014 ◽  
Vol 95 (1) ◽  
pp. 49-56 ◽  
Author(s):  
B. S. Subramanyam ◽  
M. S. N. Murty ◽  
B. S. Babu ◽  
K. V. Ramesh
2005 ◽  
Vol 9 (1) ◽  
pp. 43-72 ◽  
Author(s):  
Christo Boyadjiev

A model for transfer processes in column apparatuses has been done. The model may be modified for different apparatuses as columns with (or without) packet bed, two (or three) phase airlift reactors and fluidized bed reactors. The mass transfer is result of different volume reactions as a chemical, photochemical, biochemical or catalytic, reactions, or interphase. mass transfer. The using of the average velocities and concentration permit to solve the scale-up problems. A hierarchical approach for model parameter identification has been proposed.


1987 ◽  
Vol 65 (2) ◽  
pp. 228-236 ◽  
Author(s):  
A. Prakash ◽  
C. L. Briens ◽  
M. A. Bergougnou

Enhancement of mass transfer coefficient is highly desirable for economic design of process equipment. The present study is essentially carried out to know the effect of flow variables such as gas and liquid velocities and geometric parameters of the internal on mass transfer coefficients in a three phase fluidized bed. The mass transfer coefficient data were obtained using a string of cones internal in a three-phase fluidized bed electrochemical reactor. The flow system investigated was nitrogen, a fluid electrolyte and spherical glass beads as gas, liquid and solid phases respectively. Limiting current technique was employed to obtain mass transfer data. The internal comprises of a string of cones arranged concentrically on a central rod which is placed coaxially in a three phase fluidized bed. The presence of internal in three phase fluidized beds augmented the mass transfer coefficient significantly. In the present investigation it was found that the effect of gas velocity, liquid velocity, rod diameter and cone diameter was only marginal. However, the influence of pitch, half apex angle of cone and particle diameter was found to be significant. Correlations were developed based on least squares regression analysis for the prediction of mass transfer coefficient in terms of pertinent variables


2019 ◽  
Vol 70 (11) ◽  
pp. 4040-4046
Author(s):  
Simion Dragan

The absorption process is strongly influenced by the effective mass transfer area. In this study the effective mass transfer area in gas-solid-liquid three-phase fluidized bed was determined, in a fluidizing column having an internal diameter of 0.14 m and a height of 1.10 m. The solid packing is made of plastic hollow spheres of 0.01 m diameter, with 415 m2/m3 geometric area and a density of 170 Kg/m3. The absorption of carbon dioxide from the air-carbon dioxide mixture with molar concentration of 0.05M, 0.08M and 0.1M CO2 into sodium hydroxide aqueous solutions of 0.5N and 1.0 N has been employed as test reaction. The experiments were conducted with liquid load changing from 6.49 to 16.24 m�/(m� h) and gas velocity of 1.1 m/s and 2.1 m/s. It was found that the effective mass transfer area increased both with the increase of the gas velocity and the increase of the liquid spray density. It has been observed that the effective mass transfer area in gas-solid-liquid three-phase fluidized bed absorber is from three to eight times higher than the geometric area of the solid packing. A mathematical correlation has been established in order to predict the effective mass transfer area,under the specified conditions, with a deviation of less than 5%.


2019 ◽  
Vol 8 (3) ◽  
pp. 5763-5766

Nanomaterial has unique physical property which made it important for many applications and that is why the use of nanomaterials rapidly increasing in the field of science and engineering.1 . This work focuses on mass transfer of solids into liquid in three phase fluidized beds in presence of nanomaterial. This include the study of effect of gas velocity, time and different concentration of nanomaterials on mass transfer coefficient in stagnant liquid column in three phase fluidized bed system. To measure coefficient of the mass transfer, known quantity of solid pellets ie benzoic acid and known amount of nanomaterial fraction ie Arachitol nano were charged in the test column of three phase fluidized bed system. At the beginning of each run, test section was partially filled with water which prevent breakage of particles. The experiments were conducted by sequentially varying gas velocity for different volumes of nanomaterial and measuring the rate of mass transfer by collecting samples directly from the outlet ports at the top subsequently analysed by volumetric titration method. The results show enhancement in mass transfer coefficient by addition of nanomaterials. Arachitol nano has been taken in different volumes ie 3ml, 7ml, 10ml and 20ml in (GLS) gas ,liquid and solid fluidized bed with air, water and benzoic acid pellets as three phases respectively in the system. The presence of nanomaterial increases the solid liquid mass transfer coefficient value with increasing fraction of nanomaterial, increasing gas velocity and increasing time although experimental run has been taken only for one hour.


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