scholarly journals Absorption in a three-phase fluidized bed I: Hydrodynamic investigations

2003 ◽  
Vol 57 (7-8) ◽  
pp. 326-329 ◽  
Author(s):  
Srdjan Pejanovic
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Flow Rate ◽  
Gas Flow ◽  
Minimum Fluidization Velocity ◽  
Bed Height ◽  
Three Phase ◽  
Height Increase ◽  
Improve Mass Transfer

The hydrodynamic properties of a three phase fluidized bed with low density inert spherical packing, fluidized by the interaction of a gas flowing upwards and a liquid flowing downwards through the column, were investigated. It was found that the pressure drop, liquid hold up and dynamic bed height increase with both increasing liquid and gas flow rate. While the dynamic bed height and minimum fluidization velocity remain unchanged, both the pressure drop and liquid hold up increase with increasing density of the packing. Therefore, an increase in packing density causes more intensive mass transfer between the fluid phases than packed columns. It was shown that increase of the liquid flow rate causes an increase of both the effective liquid and gas velocity through the fluidized bed, which may also improve mass transfer.

Predicting bed dynamics in three-phase, fluidized-bed biofilm reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 231-241 ◽  
Author(s):  
H. T. Chang ◽  
B. E. Rittmann
Keyword(s):  
Fluidized Bed ◽  
Flow Rate ◽  
Liquid Flow ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Gas Flow Rate ◽  
Biofilm Growth ◽  
Biofilm Thickness ◽  
Three Phase ◽  
Proper Design

This paper presents a unified model that inter-relates gas flow rate, liquid flow rate, and hold-ups of each of the liquid, gas, and solid phases in three-phase, fluidized-bed biofilm (TPFBB) process. It describes how carrier properties, biofilm properties, and gas and liquid flow velocities control the system dynamics, which ultimately will affect the density, thickness, and distribution of the biofilm. The paper describes the development of the mathematical model to correlate the effects of gas flow rate, liquid flow rate, solid concentration, and biofilm thickness and density. This knowledge is critically needed in light of the use of TPFBB processes in treating industrial wastewater, which often has high substrate concentration. For example, the proper design of the TPFBB process requires mathematical description of the cause-effect relationship between biofilm growth and fluidization.

scholarly journals Removal of Congo Red from Aqueous Solution by Circulating Fluidized Bed(CFB)

2021 ◽  
Vol 28 (2) ◽  
pp. 01-07
Author(s):  
Hamza Q. Ali ◽  
Ahmed A. Mohammed
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Flow Rate ◽  
Congo Red ◽  
Circulating Fluidized Bed ◽  
Mass Transfer Rate ◽  
Breakthrough Curves ◽  
Solution Flow Rate ◽  
Solution Flow ◽  
Bed Height

In this study circulating fluidized bed was adopted to remove of Congo Red from wastewater using Eichhornia crassipes as a adsorbent. Solution flow rate(6,12 and 18)l/hr, bed height(2,4 and 6) cm and Congo Red initaial concentration (10,25 and 50)mg/l were examined in experiments to show their effects on breakthrough curves and time required to reach the adsorbent to fully saturated curve. The mass transfer coefficient "KL"decreased with decreasing the liquid flow rate. The minimum fluidization velocities of bed found equal to 1.6, 2, 2.5 mm/s for heights of 2, 4,6 cm respectively. The increasing of the bed height will increase the contact time of the solute in the bed, and these improve the solute removal efficiency. the increasing in flow rate and initial concentration will increase the mass transfer rate.

scholarly journals Absorption in a three-phase fluidized bed II: Mass transfer investigations

2003 ◽  
Vol 57 (7-8) ◽  
pp. 330-334
Author(s):  
Srdjan Pejanovic ◽  
Radmila Garic-Grulovic ◽  
Predrag Bozalo
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Fluidized Bed ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Interfacial Area ◽  
Transfer Coefficients ◽  
Three Phase

The absorption of carbon dioxide in aqueous diethanolamine solutions was carried out in a three-phase fluidized bed with inert spherical packing. The rate of absorption was calculated on the basis of measuring the concentration change in the liquid phase on-line by a conductivity probe. It was shown that the Danckwerts plot method might be successfully used to simultaneously determine the effective interfacial area and both the gas and liquid-side mass transfer coefficients. While the gas-side mass transfer coefficient is independent of the liquid flow rate, the effective interfacial area and liquid-side mass transfer coefficient increase with increasing liquid flow rate.

Three Phase Biofilter Model for the Removal of Styrene through the Microbial Route

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Chhaya Das ◽  
Ranjana Chowdhury ◽  
Pinaki Bhattacharya
Keyword(s):  
Mass Transfer ◽  
Kinetic Parameters ◽  
Flow Rate ◽  
Gas Flow ◽  
Reaction Model ◽  
Transfer Coefficients ◽  
Batch Type ◽  
Three Phase ◽  
Packing Size ◽  
Styrene Concentration

A biofilter of 0.05m diameter and 0.58m height has been studied for the removal of styrene from a simulated air-styrene mixture through the microbial route using Pseudomonas putida. Coconut coir and other waste materials have been used as the immobilization matrix for the microorganisms. Gas flow rate (0.005-0.01kgm-2s-1), micronutrient liquid flow rate (5-10 kgm-2s-1), inlet styrene concentration (0.05-1.20 gm-3) and packing size (de = 0.08 - 0.18cm) have been used as parameters. The kinetic parameters of growth rate equation of bacterial strain have been determined using batch type experimental data. A Monod type reaction model has been observed to be appropriate for the explanation of growth kinetics of the microorganisms. The values of the kinetic parameters used are Ks = 0.8gm-3, µmax = 45h-1. A three-phase deterministic mathematical model has been developed incorporating the synergistic effect of simultaneous reaction and interphase (gas to liquid to biofilm) mass transfer of styrene using experimentally determined kinetic parameters and mass transfer coefficients calculated using standard correlations. Simulated results based on the model have been compared with the experimental ones satisfactorily.

scholarly journals Effects of Coffee Form and Distributor Hole Angle on The Fluidization Behavior and Specific Energy Consumption in The Fluidized Bed Machine

2021 ◽  
Vol 84 (2) ◽  
pp. 152-158
Author(s):  
Thatchapol Chungcharoen ◽  
Warunee Limmun ◽  
Sansanee Sansiribhan
Keyword(s):  
Energy Consumption ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Experimental Result ◽  
Air Velocity ◽  
Minimum Fluidization Velocity ◽  
Robusta Coffee ◽  
Bed Height

The fluidized bed technique was applied to use with the Robusta coffee in this research. fluidization behavior and specific energy consumption were investigated under various coffee forms and distributor hole angles. Moreover, the minimum fluidization velocity (Vmf) was also determined. Experiments are carried out in a sample bed height of 5 cm with ambience air. In this study, two coffee forms (Ripe coffee cherries; RCC and parchment coffee; PC) and three distributor hole angles (45º, 60º and 90º) are examined. The experimental result shown that the fluidization behavior is influenced by coffee form and distributor hole angle. The RCC and distributor hole angle of 60º provided the low pressure drop throughout the superficial air velocity. The low values of Vmf and SEC were also achieved in the RCC and distributor hole angle of 60º.

Pressure Drop and Mass Transfer Studies in Liquid Fluidized Beds

2006 ◽  
Author(s):  
Bhagavatula Venkata Ramana Murthy
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Liquid Velocity ◽  
Water System ◽  
Solid Particles ◽  
Sugar Water ◽  
Minimum Fluidization Velocity ◽  
Liquid Systems ◽  
Mass Transfer Studies ◽  
Solid Liquid

Fluidized beds are widely used in industries for mixing solid particles with liquids as the solid is vigorously agitated by the liquid passing through the bed and the mixing of the solid ensures that there are practically no temperature gradients in the bed even with exothermic or endothermic reactions (Mixing and the segregation in a liquid fluidized of particles with different sizes and densities", The Canadian Journal of Chemical Engineering, 1988). The violent motion of the solid particles also gives high heat transfer rates to the wall or to cooling tubes immersed in the bed. Because of the fluidity of the solid particles, it is easy to pass solid from one vessel to another. In the present experimental work, the relative density between solid and liquid phases on pressure drop under fluidized condition has been studied using the solid-liquid systems namely, glass beads-water, glass beads-kerosene, plastic beads-kerosene and diamond sugar-kerosene. Pressure drop - liquid velocity and void fraction - liquid velocity relationships have been found for all the mentioned solid-liquid systems under fluidized condition and results have been noted. The effect of the nature of the fluid on the minimum fluidization velocity and the pressure drop has been studied. In addition to the pressure drop studies, mass transfer studies have also been conducted with diamond sugar-water system with and without fluidization and results have been obtained. In addition to these, comparison of bed voidage, pressure drop and minimum fluidization velocity between denser and lighter liquids have been studied and the results have been obtained. Also, the value of rate of mass transfer with fluidization is compared that without fluidization for diamond sugar-water system and the results have been obtained.

Influence of Gas-Liquid Distribution Inducer on Mass Transfer Coefficient in Rotating Packed Bed

2014 ◽  
Vol 908 ◽  
pp. 277-281
Author(s):  
Fei Wu ◽  
Jie Wu ◽  
Mei Jin ◽  
Fang Wang ◽  
Ping Lu
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Rotor Blade ◽  
Gas Flow ◽  
Packed Bed ◽  
Contact Length ◽  
Liquid Distribution ◽  
Rotating Packed Bed

Based on acetone-H2O system, the influence of the gas-liquid distribution inducer on the mass transfer coefficient in the rotating packed bed with the stainless steel packing was investigated. Furthermore, the absorption performance was also obtained under the experimental condition of the rotational speed of 630 rpm, the gas flow rate of 2 m3/h and the liquid flow rate of 100 L/h in the rotating packed bed with different types and different installation ways of the distribution inducer. The experimental results showed that the volumetric mass transfer coefficient Kyα per unit contact length of gas-liquid was increased by 8.6% for the forward-curved fixed blade, by 19.8% for the backward-curved rotor blade and by 33.2% with the combination of the straight radial rotor blade and the backward-curved fixed blade, respectively. Furthermore, when the gas flow rate was 2.5 m3/h, Kyα per unit contact length of gas-liquid was increased by 2.9% for the forward-curved fixed blade, by 25.3% for the backward-curved rotor blade, by 42.7% for the combination of the straight radial rotor blade and the backward-curved fixed blade, respectively. The results indicated that the distribution inducer play an important role on the improvement of the mass transfer coefficient in acetone-H2O system.

The Pressure Drop at Critical Fluidization of Large Particles in Vibrated Fluidization Bed

2012 ◽  
Vol 550-553 ◽  
pp. 2763-2766
Author(s):  
Xue Jun Zhu ◽  
Jun Deng
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Large Particle ◽  
Particle Diameter ◽  
Future Design ◽  
Vibration Strength ◽  
Bed Height ◽  
Large Particles ◽  
Vibrated Fluidized Bed ◽  
Critical Fluidization

The pressure drop at critical fluidization for two-dimensional vibrated fluidized bed(240 mm×80 mm) was studied, with large particle glass beads of average diameters dp of 1.8mm, 2.5mm and 3.2mm.The effect of the vibration strength, the static bed height and the particle diameter on the pressure drop was analyzed. The results of the study show that the pressure drop decreases with the increase of the vibration strength. It plays an even more prominent part with decreases of the static bed height and the particle diameter. The empirical correlation equations to predict the pressure drop was established, and the results of the prediction was compared with the experimental data, the error is in range of ±10%. The results can provide references for future design and research on the vibrated fluidized bed.

scholarly journals Diffusion models and scale-up

2005 ◽  
Vol 9 (1) ◽  
pp. 43-72 ◽  
Author(s):  
Christo Boyadjiev
Keyword(s):  
Mass Transfer ◽  
Parameter Identification ◽  
Fluidized Bed ◽  
Scale Up ◽  
Catalytic Reactions ◽  
Fluidized Bed Reactors ◽  
Hierarchical Approach ◽  
Model Parameter ◽  
Transfer Processes ◽  
Three Phase

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.

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