Influence of fluid-mechanical characteristics of the system on the volumetric mass transfer coefficient and gas dispersion in three-phase system

Distribution of gas bubbles and volumetric mass transfer coefficient, Kla, in a three phase system, with different types of solid particles at different operation conditions were studied in this paper. The ranges of superficial gas and liquid velocities used in this study were 0,03-0,09 m/s and 0-0,1 m/s, respectively. The three different types of solid particles were used as a bed in the column (glass dp=3 mm, dp=6 mm; ceramic dp=6 mm). The experiments were carried out in a 2D plexiglas column, 278 x 20,4 x 500 mm and in a cylindrical plexiglas column, with a diameter of 64 mm and a hight of 2000 mm. The Kla coefficient increased with gas and liquid velocities. Results showed that the volumetric mass transfer coefficient has a higher values in three phase system, with solid particles, compared with two phase system. The particles properties (diameter and density) have a major impact on oxygen mass transfer in three phase systems.

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Influence of suspended solid particles on gas-liquid mass transfer coefficient in a system stirred by double impellers

Chemical Papers ◽

10.2478/s11696-009-0013-y ◽

2009 ◽

Vol 63 (2) ◽

Cited By ~ 3

Author(s):

Anna Kiełbus-Rąpała ◽

Joanna Karcz

Keyword(s):

Mass Transfer ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

High Speed ◽

Gas Flow ◽

Research Work ◽

Experimental Studies ◽

Solid Particles ◽

Solid Concentration ◽

Volumetric Mass Transfer Coefficient

AbstractThe aim of the research work was to investigate the effect of the presence and concentration of solid particles on the gas-liquid volumetric mass transfer coefficient in a mechanically stirred gas-solid-liquid system. Experimental studies were conducted in a tall vessel of the diameter of 0.288 m, equipped with two designs of double stirrers. Three high-speed stirrers were used: A 315, Smith turbine, and Rushton turbine. The following operating parameters were changed: gas flow rate, stirrer speed, and solid concentration. The volumetric mass transfer coefficient was determined using the dynamic gassing-out method. In the range of the measurements conducted, this coefficient was strongly affected by both the presence and the concentration of particles in the system. Generally, a low concentration of particles in the system, equal to 0.5 mass %, caused an increase of the volumetric mass transfer coefficient values for both stirrer configurations compared to a system without solids whilst more particles (2.5 mass %) caused a decrease of this coefficient. It could be supposed that an increase of slurry viscosity affected the decrease of the volumetric mass transfer coefficient at higher solid concentration. An empirical correlation was proposed for volumetric mass transfer coefficient prediction. Its parameters were fitted using experimental data.

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A three-phase Robinson-Mahoney reactor as a tool for intrinsic kinetic measurements: Determination of gas-liquid hold up and volumetric mass transfer coefficient

Chemical Engineering Science ◽

10.1016/j.ces.2017.02.041 ◽

2017 ◽

Vol 170 ◽

pp. 694-704 ◽

Cited By ~ 1

Author(s):

Jeroen Lauwaert ◽

Chetan S. Raghuveer ◽

Joris W. Thybaut

Keyword(s):

Mass Transfer ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Volumetric Mass Transfer Coefficient ◽

Kinetic Measurements ◽

Three Phase ◽

Intrinsic Kinetic

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Absorption Performance of Rotating Packed Bed with Gas-Liquid Distribution Inducer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1010-1012.913 ◽

2014 ◽

Vol 1010-1012 ◽

pp. 913-916

Author(s):

Mei Jin ◽

Li Zhan ◽

Li Yan Zhou ◽

Guo Xian Yu ◽

Ping Lu

Keyword(s):

Mass Transfer ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Gas Phase ◽

Packed Bed ◽

Volumetric Mass Transfer Coefficient ◽

Liquid Distribution ◽

Rotating Packed Bed ◽

Different Types ◽

Absorption Performance

Based on CO2-NaOH system, the absorption performances and the mass transfer of the rotating packed bed with the three different types of the gas-liquid distribution inducer were investigated. The experimental results showed that the structure of the gas-liquid distribution inducer have an important effect on the volumetric mass transfer coefficient and the absorptivity of CO2. Due to the enhancement of the countercurrent contact between the liquid phase and the gas phase from the installation of the distribution inducer, an increasement of the volumetric mass transfer coefficient and a higher absorptivity of CO2 could be obtained than those of the experiment in PRB without any inducers. Among the distribution inducers, the combination of the liquid distribution inducer of Type-B and the gas distribution inducer of Type-A could give a better volumetric mass transfer coefficient and a higher absorptivity of CO2, which were 27.84×10-3 s-1 and 80.00%, respectively.

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Artificial Neural Network for Prediction of SO2 Removal and Volumetric Mass Transfer Coefficient in Spray Tower

Chemical Engineering Research and Design ◽

10.1016/j.cherd.2021.03.008 ◽

2021 ◽

Author(s):

Vinícius Y. Valera ◽

Milene C. Codolo ◽

Tiago D. Martins

Keyword(s):

Neural Network ◽

Mass Transfer ◽

Artificial Neural Network ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Volumetric Mass Transfer Coefficient ◽

Spray Tower ◽

So2 Removal ◽

Artificial Neural

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Gas–liquid mass transfer characteristics of aviation fuel scrubbing in an aircraft fuel tank

Scientific Reports ◽

10.1038/s41598-021-94786-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Li Chaoyue ◽

Feng Shiyu ◽

Xu Lei ◽

Peng Xiaotian ◽

Yan Yan

Keyword(s):

Mass Transfer ◽

Dissolved Oxygen ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Oxygen Concentration ◽

Gas Holdup ◽

Aviation Fuel ◽

Volumetric Mass Transfer Coefficient ◽

Dissolved Oxygen Concentration ◽

Liquid Mass Transfer

AbstractDissolved oxygen evolving from aviation fuel leads to an increase in the oxygen concentration in an inert aircraft fuel tank ullage that may increase the flammability of the tank. Aviation fuel scrubbing with nitrogen-enriched air (NEA) can largely reduce the amount of dissolved oxygen and counteract the adverse effect of oxygen evolution. The gas–liquid mass transfer characteristics of aviation fuel scrubbing are investigated using the computational fluid dynamics method, which is verified experimentally. The effects of the NEA bubble diameter, NEA superficial velocity and fuel load on oxygen transfer between NEA and aviation fuel are discussed. Findings from this work indicate that the descent rate of the average dissolved oxygen concentration, gas holdup distribution and volumetric mass transfer coefficient increase with increasing NEA superficial velocity but decrease with increasing bubble diameter and fuel load. When the bubble diameter varies from 1 to 4 mm, the maximum change of descent rate of dissolved oxygen concentration is 18.46%, the gas holdup is 8.73%, the oxygen volumetric mass transfer coefficient is 81.45%. When the NEA superficial velocities varies from 0.04 to 0.10 m/s, the maximum change of descent rate of dissolved oxygen concentration is 146.77%, the gas holdup is 77.14%, the oxygen volumetric mass transfer coefficient is 175.38%. When the fuel load varies from 35 to 80%, the maximum change of descent rate of dissolved oxygen concentration is 21.15%, the gas holdup is 49.54%, the oxygen volumetric mass transfer coefficient is 44.57%. These results provide a better understanding of the gas and liquid mass transfer characteristics of aviation fuel scrubbing in aircraft fuel tanks and can promote the optimal design of fuel scrubbing inerting systems.

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Mass Transfer Coefficients during Steel Decarburization in a RH Degasser

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.273-276.679 ◽

2008 ◽

Vol 273-276 ◽

pp. 679-684

Author(s):

Roberto Parreiras Tavares ◽

André Afonso Nascimento ◽

Henrique Loures Vale Pujatti

Keyword(s):

Mass Transfer ◽

Reynolds Number ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Gas Flow ◽

Vacuum Chamber ◽

Volumetric Mass Transfer Coefficient ◽

Gas Flow Rate ◽

Rh Process ◽

Kinetics Of

The RH process is a secondary refining process that can simultaneously attain significant levels of removal of interstitial elements, such as carbon, nitrogen and hydrogen, from liquid steel. In the RH process, the decarburization rate plays a very important role in determining the productivity of the equipment. The kinetics of this reaction is controlled by mass transfer in the liquid phase. In the present work, a physical model of a RH degasser has been built and used in the study of the kinetics of decarburization. The effects of the gas flow rate and of the configurations of the nozzles used in the injection of the gas have been analyzed. The decarburization reaction of liquid steel was simulated using a reaction involving CO2 and caustic solutions. The concentration of CO2 in the solution was evaluated using pH measurements. Based on the experimental results, it was possible to estimate the reaction rate constant. A volumetric mass transfer coefficient was then calculated based on these rate constants and on the circulation rate of the liquid. The logarithm of the mass transfer coefficient showed a linear relationship with the logarithm of the gas flow rate. The slope of the line was found to vary according to the relevance of the reaction at the free surface in the vacuum chamber. A linear relationship between the volumetric mass transfer coefficient and the nozzle Reynolds number was also observed. The slopes of the lines changed according to the relative importance of the two reaction sites, gas-liquid interface in the upleg snorkel and in the vacuum. At higher Reynolds number, the reaction in the vacuum chamber tends to be more significant.

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