Computation of the mass transfer coefficient of FCC particles in a thin bubbling fluidized bed using two- and three-dimensional CFD simulations

2011 ◽  
Vol 66 (22) ◽  
pp. 5602-5613 ◽  
Author(s):  
Benjapon Chalermsinsuwan ◽  
Pornpote Piumsomboon
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Fluidized Bed ◽  
Three Dimensional ◽  
Cfd Simulations ◽  
Bubbling Fluidized Bed

scholarly journals Electro Winning from Dilute Solutions at Enhanced Rates using Three-Phase Flow Reactor

2020 ◽  
Vol 9 (4) ◽  
pp. 1740-1745
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Fluidized Bed ◽  
Flow Reactor ◽  
Liquid Velocity ◽  
Particle Diameter ◽  
Limiting Current ◽  
Process Equipment ◽  
Three Phase

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

Three-Dimensional Simulation of Bubble Behavior and Mass Transfer for CO2 Absorption in Nanoabsorbents

2019 ◽  
Author(s):  
Lirong Li ◽  
Yong Tae Kang
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Three Dimensional ◽  
Particle Method ◽  
Liquid System ◽  
Al2o3 Nanoparticles ◽  
Co2 Absorption ◽  
Gas Bubble ◽  
Surface Renewal

Abstract CO2 absorption performance in gas-liquid system is affected by nanoparticles. The enhancement mechanisms involved have been extensively paid attention. The CO2 gas bubble behaviors and the characteristics of the nanoparticle motion have been clarified in the present study. The equivalent substitution method is used to regard the liquid with nanoparticles as a continuous term with changed physical properties, that is, nanofluid. Therefore, the volume-of-fluid (VOF) method is employed to well predict the gas bubble behaviors and mass transfer coefficient in nanofluid. It is found that the mass transfer coefficient in the gas-liquid system for CO2 absorption can be significantly enhanced by Al2O3 nanoparticles. With the increase of nanoparticles volume concentration, the surface renewal frequency increases dramatically. The discrete-particle-method (DPM) is adopted to track the motion of nanoparticles. In this way, the deformation of the bubbles and the motion of the nanoparticle are well captured. It is concluded that the enhanced mass transfer coefficient in gas-liquid-nanoparticle system is not only related to the Brownian motion of the particles, but also related to the nanoparticle deduced turbulence in the liquid field.

scholarly journals A novel two-phase model for bubbling fluidized-bed CO-methanation reactor

2020 ◽  
Author(s):  
Quancong Zhang ◽  
Zhikai Cao ◽  
Songshou Ye ◽  
Yong Sha ◽  
Bing Hui Chen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Fluidized Bed ◽  
Gas Flow ◽  
Flow Distribution ◽  
Co Methanation ◽  
Interphase Mass Transfer ◽  
Proposed Model

Fluidized bed reactor is promising for CO methanation owing to its excellent heat transfer performance. The gas flow distribution between the bubble and emulsion phases and mass transfer are important for such a solid-catalyzed fast reaction in fluidized bed but these are described simplistically in most conventional models. In this work, a novel model contemplating the gas flow distribution influenced by circulation flow and the interphase mass transfer coefficient influenced by bubble size variation is proposed. The simulation results of the proposed model and the classic Kunii–Levenspiel model were compared with experimental data of fluidized bed CO methanation. It was shown that the results of the proposed model have better agreement with experimental data. To evaluate the roles of gas flow distribution and interphase mass transfer coefficient, sensitivity analysis was carried out. The results indicated that in the proposed model, the effect of gas flow distribution is more important.

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