scholarly journals Effect of particles on hydrodynamics and mass transfer in a slurry bubble column: Correlation of experimental data

Author(s):  
Huahai Zhang ◽  
Zhongshan Guo ◽  
Yuelin Wang ◽  
Xiankun Shen ◽  
Tiefeng Wang

The effects of particle concentration and size on hydrodynamics and mass transport in a slurry bubble column were experimentally studied. With increasing particle concentration, the averaged gas holdup, gas holdup of small bubbles and gas-liquid volumetric mass transfer coefficient decreased, while the gas holdup of large bubbles increased slightly. With increasing particle size, the averaged gas holdup and kla remained unchanged when the particle size increased from 55 to 92 m, but decreased significantly when the particle size was further increased to 206 m. A liquid turbulence attenuation model which could quantitatively describe the effects of particle concentration and size was first proposed. Semi-empirical correlations were obtained based on extensive experimental data in a wide range of operating conditions and corrected liquid properties. The gas holdup and mass transfer coefficient calculated by the correlations agreed with the experimental data from both two-phase and three-phase bubble columns

2015 ◽  
Vol 69 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Milica Djekovic-Sevic ◽  
Nevenka Boskovic-Vragolovic ◽  
Ljiljana Takic ◽  
Radmila Garic-Grulovic ◽  
Srdjan Pejanovic

Experimental investigation of gas-liquid mass transfer of ozone in water, in bubble column with two-fluid nozzle gas distributor (BKDM), under different operating conditions, are presented in this work. The main objective was to determine the ozone volumetric mass transfer coefficient, kL a, in calm uniform section of the column, under different values of gas and liquid flow rates. Obtained values of these coefficients were compared with the values in countercurrent bubble column. The critical liquid flowrate, when gas hold up reaches its maximum, was experimentally determined. It was shown that the maximum value of the ozone volumetric mass transfer coefficient is obtained just when liquid flowrate is at its critical value.


2016 ◽  
Vol 22 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Xiaolei Li ◽  
Chunying Zhu

In this study, the mass transfer accompanied by an instantaneous irreversible chemical reaction in a slurry bubble column containing sparingly soluble fine reactant particles has been analyzed theoretically. Based on the penetration theory, combining the cell model, a one-dimensional mass transfer model was developed. In the model, the effects of the particle size and the particle dissolution near the gas-liquid interface on the mass transfer were taken into account. The mass transfer model was solved and an analytical expression of the time-mean mass transfer coefficient was attained. The reactive absorption of SO2from gas mixtures into Mg(OH)2/water slurry was investigated experimentally in a bubble column reactor to validate the mass transfer model. The results indicate that the present model has good predicting performance and could be used to predict mass transfer coefficient for the complicated gas-liquid-solid three-phase system with an instantaneous irreversible chemical reaction.


2006 ◽  
Vol 32 (6) ◽  
pp. 471-476
Author(s):  
Yuichi Ohira ◽  
Takeshi Sakai ◽  
Hiroshi Takahashi ◽  
Eiji Obata ◽  
Koji Ando

2013 ◽  
Vol 11 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Laleh Hadavand ◽  
Ali Fadavi

Abstract Bubble size has a key role in gas holdup and mass transfer in bubble column reactors. In order to have small and uniform bubbles, a new structure was designed; the reactor operates in two modes, with vibrating sparger and conventional bubble column in which sparger is fixed. In vibrating mode, the sparger vibrates gently during gas entering. The vibrating sparger performs like a paddle, resulting in a forced recirculation of gas–liquid inside the reactor; moreover, the bubble detachment is accelerated. The superficial gas velocity was between 0.003 and 0.013 ms− 1, and the vibration frequency was changed between 0 and 10.3 Hz. The bubble size was measured at three various positions of the reactor height by photographic method and using MATLAB 7.0.1 software. The mass transfer coefficient was determined by means of the dynamic gassing-out method. The results show that the bubbles were bigger in vibrating mode than those working without vibration. The bubble size decreases with increase in height from sparger. Gas holdup increased with increase in superficial gas velocity and vibration frequency. The effect of vibration increased the gas holdup with an average of 70% for all superficial gas velocities. Volumetric mass transfer coefficient was almost stable as vibration frequency increased.


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