CFD simulation of continuous non-catalytic gas-solid reaction with uniform particle size distribution

2021 ◽  
pp. 117168
Author(s):  
Zheng Zou ◽  
Xu Zhang ◽  
Dong Yan ◽  
Ruixiang Tang ◽  
Qingshan Zhu ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Cfd Simulation ◽  
Solid Reaction ◽  
Uniform Particle Size ◽  
Gas Solid Reaction

scholarly journals CFD simulation of solids suspension in stirred tanks: Review

2010 ◽  
Vol 64 (5) ◽  
pp. 365-374 ◽  
Author(s):  
Aoyi Ochieng ◽  
Mrice Onyango
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Concentration Distribution ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Cfd Modeling ◽  
Small Scale ◽  
Stirred Tanks ◽  
Solids Concentration

Many chemical reactions are carried out using stirred tanks, and the efficiency of such systems depends on the quality of mixing, which has been a subject of research for many years. For solid-liquid mixing, traditionally the research efforts were geared towards determining mixing features such as off-bottom solid suspension using experimental techniques. In a few studies that focused on the determination of solids concentration distribution, some methods that have been used have not been accurate enough to account for some small scale flow mal-distribution such as the existence of dead zones. The present review shows that computational fluid dynamic (CFD) techniques can be used to simulate mixing features such as solids off-bottom suspension, solids concentration and particle size distribution and cloud height. Information on the effects of particle size and particle size distribution on the solids concentration distribution is still scarce. Advancement of the CFD modeling is towards coupling the physical and kinetic data to capture mixing and reaction at meso- and micro-scales. Solids residence time distribution is important for the design; however, the current CFD models do not predict this parameter. Some advances have been made in recent years to apply CFD simulation to systems that involve fermentation and anaerobic processes. In these systems, complex interaction between the biochemical process and the hydrodynamics is still not well understood. This is one of the areas that still need more attention.

CFD Simulation of Spouted Bed Working with a Size Distribution of Sand Particles: Segregation Aspects

2017 ◽  
Vol 899 ◽  
pp. 95-100
Author(s):  
Kássia Graciele dos Santos ◽  
L.V. Ferreira ◽  
Ricardo Correa Santana ◽  
Marcos Antonio de Souza Barrozo
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Cfd Simulation ◽  
Computational Simulation ◽  
Particle Diameter ◽  
Spouted Bed ◽  
Particle Segregation ◽  
Cfd Method ◽  
Mean Particle Diameter

Spouted bed simulations are usually performed using only one granular phase with a mean particle diameter representing the entire particle mixture, instead of a particle size distribution. In this study, the effect of the particle size distribution is accounted through the simulation of a mixture with five granular phases. The results showed that the particle segregation occurs. Larger particles are more concentrated in the upper region, while the smaller particles are preferably positioned in the lower region of the bed. Computational simulation using CFD method reproduced well the segregation experiments with different participle sizes of sand.

The Effect of Uniform Particle Size Distribution on Pt Stability

2019 ◽  
Vol 41 (1) ◽  
pp. 761-773 ◽  
Author(s):  
Panagiotis Trogadas ◽  
Thomas F. Fuller
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Uniform Particle Size

scholarly journals Surfactant-Assisted Sol-Gel Synthesis of TiO2 with Uniform Particle Size Distribution

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
O. L. Galkina ◽  
V. V. Vinogradov ◽  
A. V. Agafonov ◽  
A. V. Vinogradov
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Sol Gel ◽  
Active Surface ◽  
Titanium Isopropoxide ◽  
Active Surface Area ◽  
Vis Spectroscopy ◽  
Uniform Particle Size ◽  
Surfactant Assisted

TiO2 materials were prepared from a titanium isopropoxide precursor by sol-gel processing in water media with or without various templates (polyethylenimine or Pluronic P-123). The photocatalytic efficiency of the samples was found to depend strongly on the use of and type of template added. Titania/Pluronic sols resulted in homogeneous anatase TiO2—rutile with uniform particle size distribution after calcination (400°C). Optical properties of the samples were characterized by UV-Vis spectroscopy and crystalline structures by X-ray diffraction. A surfactant-assisted sol-gel process retarded crystallization of the anatase and rutile titania, which resulted in smaller grain sizes and presumably a larger active surface area. The morphology of the surfaces was obtained by AFM techniques. The highest photobleaching rate was found for samples deposited from the sol with the addition of the Pluronic P-123 surfactant, and it was almost twice as high as that for films deposited from sols with polyethylenimine.

scholarly journals Particle Lagrangian CFD Simulation and Experimental Characterization of the Rounding of Polymer Particles in a Downer Reactor with Direct Heating

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 916
Author(s):  
Juan S. Gómez Bonilla ◽  
Laura Unger ◽  
Jochen Schmidt ◽  
Wolfgang Peukert ◽  
Andreas Bück
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Residence Time ◽  
Cfd Simulation ◽  
Numerical Approach ◽  
Particle Dispersion ◽  
Direct Heating ◽  
Residence Time Distributions ◽  
Downer Reactor

Polypropylene (PP) powders are rounded at different conditions in a downer reactor with direct heating. The particles are fed through a single central tube, while the preheated sheath gas is fed coaxially surrounding the central aerosol jet. The influence of the process parameters on the quality of the powder product in terms of particle shape and size is analyzed by correlating the experimental results with the flow pattern, residence time distribution of the particles and temperature distribution predicted by computational fluid dynamics (CFD) simulations. An Eulerian–Lagrangian numerical approach is used to capture the effect of the particle size distribution on the particle dynamics and the degree of rounding. The simulation results reveal that inlet effects lead to inhomogeneous particle radial distributions along the total length of the downer. The configuration of particle/gas injection also leads to fast dispersion of the particles in direction of the wall and to particle segregation by size. Broad particle residence time distributions are obtained due to broad particle size distribution of the powders and the particles dispersion towards the wall. Lower mass flow ratios of aerosol to sheath gas are useful to reduce the particle dispersion and produce more homogenous residence time distributions. The particles’ residence time at temperatures above the polymer’s melting onset is determined from the simulations. This time accounts for the effective treatment (rounding) time of the particles. Clear correlations are observed between the numerically determined effective rounding time distributions and the progress of shape modification on the particles determined experimentally.

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