Size segregation of binary mixture of solids in bubbling fluidized beds

Huilin, Lu; He, Yurong; Gidaspow, Dimitri; Yang, L.; Yu-kun, Qin

doi:10.1016/s0032-5910(03)00126-8

Cited by 158 publications

(58 citation statements)

References 30 publications

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“…Fluidization velocities ranged from 0.148-0.384 m/s. Huilin et al (2003) measured segregation of binary mixtures with typical experimental results. Segregation was measured using the vacuum method.…”

Section: Literature Reviewmentioning

confidence: 83%

Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

Banerjee¹,

Chen²,

Patel³

et al. 2008

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Executive SummaryDense gas-solid reactors are used throughout the chemical industry for catalytic reaction processes including hydrocarbon cracking, Fischer-Tropsch synthesis, and production of titanium dioxide, polyethylene, and many other chemicals. In addition, fluidized beds are used for non-catalytic reaction processes including chlorination, oxidation, roasting, calcinations, combustion, incineration, heat treatment, coatings, and many others. However, understanding, control, and scale-up of these processes are limited by difficulties in measurement and modeling the dense solid-particle flow. Millennium Inorganic Chemicals, Inc. (MIC) and ExxonMobil Research and Engineering (EMRE), and Sandia National Laboratories (SNL) formed a multidisciplinary team with CPFD Software, LLC (CPFD), to conduct a three-year research program to provide advanced analysis capability in solid-fluid reactors, with broad extensions to catalysis, thermal cracking, gas-solid separation, and solid chemistry. This project focused specifically on chemical issues in fluidized-bed applications. The direct application is the chemistry in ExxonMobil's Fluid Coking™ processes and in the MIC titanium tetrachloride production pricess, but this development has broader benefits through the ability to better predict and control flow and chemistry in dense gas-solid reactors.The work performed under this DOE grant focused on the Technology Vision 2020: This work relates to Reactions and Particulate Processes, specifically within Technology Area 1 -Chemical Synthesis.The work completed under this grant addresses Enabling Technologies within Computational Technology by integrating a "breakthrough" particle-fluid computational technology into traditional Process Science and Engineering Technology. The work completed under this DOE grant addresses five major development areas 1) gas chemistry in dense fluidized beds 2) thermal cracking of liquid film on solids producing gas products 3) liquid injection in a fluidized bed with particle-to-particle liquid film transport 4) solid-gas chemistry and 5) first level validation of models. Because of the nature of the research using tightly coupled solids and fluid phases with a Lagrangian description of the solids and continuum description of fluid, the work provides ground-breaking advances in reactor prediction capability.The advanced computational models for chemistry and liquid-jet for reactor design and operation was implemented in the commercial computational particle fluid dynamics (CPFD) package (Barracuda™). This report includes five topical reports with the first four describing the chemistry and liquid jet functionality and where possible compares calculations with experimental data. The final report outlines some of the experiments that were performed as well as proposed experiments that had to be postponed or eliminated due to funding restrictions. In addition, the report outlines the steps taken to commercialize the product arising from this joint effort. ENHANCED PRODUCTIVITY OF CHEMICAL PROC...

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Section: Literature Reviewmentioning

confidence: 83%

Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

Banerjee¹,

Chen²,

Patel³

et al. 2008

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“…The gas flow increase within the fluidized bed will confer more Lateral velocity results showed that MSW particles revealed a generalized increased axial velocity at both bed heights, particularly in the center bed regions, when compared to dolomite particles. MSW due to being the lighter component showed increased axial velocity, while the heavier dolomite revealed inferior axial movement [39]. However, a high reaching peak can be seen for both dolomite profiles (8 and 16 cm) in the right near wall region about 0.50 m (Figure 8b,d).…”

Section: Time-mean Volume Fraction and Solid Particles Velocity Profilesmentioning

confidence: 92%

“…Indeed, as the inlet velocity is increased, higher axial velocity is measured in the near wall regions. The gas flow increase within the fluidized bed will confer more kinetic energy into the solid particles, increasing the turbulence effect, and in turn, the lateral solids dispersion, which may be compelling the solid particles to move towards the reactor's walls increasing the axial near wall velocity [39]. Concerning the bed height, the profiles showed a higher particle velocity at 16 cm height than at 8 cm height.…”

Section: Time-mean Volume Fraction and Solid Particles Velocity Profilesmentioning

confidence: 99%

“…However, a high reaching peak can be seen for both dolomite profiles (8 and 16 cm) in the right near wall region about 0.50 m (Figure 8b,d). Such an effect may be due to a lateral acceleration induced by bubbles over the dolomite particles towards the wall region [39]. Indeed, as the inlet velocity is increased, higher axial velocity is measured in the near wall regions.…”

Section: Time-mean Volume Fraction and Solid Particles Velocity Profilesmentioning

confidence: 99%

“…The higher the superficial gas velocity is, the higher the drag force exerted upon the solid particles will be, leading to an increased particles velocity. However, some peaks from the 0.25 m/s profile are seen to surpass the 0.40 m/s profile, this may be given to the particles collisions and chaotic flow induced by greater velocities, casting solid particles into lateral opposing directions resulting in reduced axial velocity [39]. …”

Section: Time-mean Volume Fraction and Solid Particles Velocity Profilesmentioning

confidence: 99%

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Hydrodynamic Modelling of Municipal Solid Waste Residues in a Pilot Scale Fluidized Bed Reactor

et al. 2017

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Abstract:The present study investigates the hydrodynamics and heat transfer behavior of municipal solid waste (MSW) gasification in a pilot scale bubbling fluidized bed reactor. A multiphase 2-D numerical model following an Eulerian-Eulerian approach within the FLUENT framework was implemented. User defined functions (UDFs) were coupled to improve hydrodynamics and heat transfer phenomena, and to minimize deviations between the experimental and numerical results. A grid independence study was accomplished through comparison of the bed volume fraction profiles and by reasoning the grid accuracy and computational cost. The standard deviation concept was used to determine the mixing quality indexes. Simulated results showed that UDFs improvements increased the accuracy of the mathematical model. Smaller size ratio of the MSW-dolomite mixture revealed a more uniform mixing, and larger ratios enhanced segregation. Also, increased superficial gas velocity promoted the solid particles mixing. Heat transfer within the fluidized bed showed strong dependence on the MSW solid particles sizes, with smaller particles revealing a more effective process.

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