Outline of Particle Technology - ERPT

Outline of Particle Technology - ERPT

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Educational Resources for Particle Technology
an archived electronic journal of reviewed contributions

Outline of Particle Technology

Latest changes: 03Dec03 - more on safety, inclusion in courses / 05Oct24 - grey borders /

The topics noted below might be included in courses that are currently part of the engineering curriculum but deal with only continuous phases (not particulates or droplets).**

EPRT has tutorials covering some of these topics, and our goal is to cover them all by 2010. We welcome contributions of tutorials, posted either on your own Web site or on the EPRT site. To discuss this contact the managing editor.

Jump to any section noted below:

1. The Significance of Particle Technology
2. Making, Merging, and Breaking Particles
3. Physics of Particles
….. Physical Methods for Characterizing Particles
4. Storage and Transport of Particulates
5. Mixing and Separation of Particulate; l
6. Thermal Interactions in Particulate Systems
7. Chemical Interactions in Particulate Systems
8. Mathematical Techniques for Particulate Systems
9. Health, Safety, and Environmental Concerns
10. Specific Applications of Particle Technology

1. The Significance of Particle Technology

  • in Industrial Processes
  • in the Environment
  • in Research Opportunities

2. Making, Merging, and Breaking Particles

Chemical Methods to Make Particles

  • Precipitation from a Gas Phase - condensation, evaporation, effect of nuclei, crystallization, agglomeration/sintering
  • Precipitation from a Liquid Phase - nucleation, precipitation, dissolution, Ostwald ripening, crystallization, agglomeration/sintering, precipitation in emulsions, effect of secondary solutes
  • Mutation from another solid phase
  • Encapsulation - physical, precipitation, chemical transmutation Physical Methods to Make Larger Particles
  • Compaction - application and propogation of impact forces
  • Sintering
  • Granulation
  • Agglomeration - liquid bridges, solid bridges (formation and removal), diffusion, mixing, local shear Physical Methods to Make Smaller Particles
  • Comminution
  • Attrition
  • Extrusion
  • Chopping
  • Application and propogation of uni-axial slow forces

3. Physics of Particles

Particle Contact Interactions (Tribology)

  • Particle-Particle Iteraction - contact forces, van der Waals, charge, magnetic, etc.
  • Particle-Field Interaction (Gas and Liquid Phase) - thermal diffusion, sedimentation (gravity, centrifugal), electrodrift (zeta potential), magnetic, radiation pressure for particle trapping, light scattering (Mie, Rayleigh, etc.)
  • Effect of Loading on Particle-Field Response - hindered settling, etc. Particle-Wall Interactions, Use in Characterization
  • particle-wall impact, attrition, and wear
  • tribo-charging
  • surface stress generation, mechanochemistry
  • electrochemical cell formation due to deposition
  • detergency and removal of wall deposits
  • gas-phase wall deposition and re-entrainment (time effects)
  • fouling, sediment beds and resuspension (time effects) Physical Methods for Characterizing Particles

  • Notes on Sampling (flow, whole stream, changes on standing, problems due to segregation based on composition or size )

  • Density (specific gravity)

  • Hardness

  • Tribocharging

  • Size Distribution
    … light scattering (Mie, Rayleigh, etc.)
    … sedimentation
    … electrotransport

  • Pore Size Distribution

  • Shape, Surface Roughness

  • Crystal habit, domain size

  • Evaluation of Chemical Composition (bulk, surface)

4. Storage and Transport of Particles

Piles, Silos, and Bins (fill, stand, discharge)

  • Angle of Repose
  • Bulk Density (Consolidation, packing, and time effects)
  • Spacial Distribution of Bulk Density
  • Level, shape of top during fill, discharge
  • Mohr circle, wall friction, stresses in bulk and on wall consolidation
  • design and testing, level detection Bin Flow Problems
  • arch formation, cohesive strength, heel in silo
  • flow function, flow factor, discharge flow patterns
  • bin design, testing, discharge rate and pattern indicators
  • flow discharge aids
  • explosive aerators, vibrators, arch breakers, delumpers
  • effect of vibration and condensation cycling in rail cars
  • valves and flow restricting (metering) devices (feeders) Bed Transport - trucks, belts, bucket elevators

Cascade Transport - chute flow, screw feeders

Flow Aids - agglomeration, additives, coatings, surface treatments

Fluidized Transport

  • permeability to Flow (gas, liquid)
  • measuring spacial distribution of particulates (tomography)
  • fluidization (non-cohesive, cohesive)
  • pneumatic conveying (saltation, dune flow, dense phase conveying, choking flow), standpipes
  • blower selection and operation with powders
  • measurement and control of effective fluidized viscosity
  • pressure drop, monitoring flow and pressure Transport and Storage of Powders
  • conveying in slurry form
  • measurement and control of rheology
  • pump selection and operation with slurries
  • pressure drop, monitoring flow and pressure
  • stirred tanks, agitator blade design and placement
  • agitator motor selection for startup and settled conditions
  • distribution of solids due to settling and centrifugation
  • effect of vibration and Ostwald ripening in rail cars

5. Mixing and Separation of Particles

Mixing Powders

  • quantitative theory, implications for analysis
  • powder mixers
    .. mechanical, power requirements
    .. pneumatic, (batch, continuous)
    .. metering and monitoring flows and compostion
    .. methods for assessing mixing

  • liquids
    .. points of addition, points for sampling (batch, continuous)
    .. methods for assessing mixing Mixing With a Gas

  • fluidization (gas)
    .. bed expansion, bubbling, distributors
    .. heat and mass transfer

  • feeders and distributors into gas systems Mixing With a Liquid

  • wetting into liquids

  • feeders and distributors into liquid systems

  • fluidization in liquids Separation from a Gas Phase

  • filters, cyclones, electrostatic, magnetic

  • grade efficiency curves

  • blockage, abrasion, fouling, bypass

  • series and parallel operation Separation from a Liquid Phase

  • sedimentation (batch, continuous), thickening, flocculation

  • centrifugation (batch, continuous), cake compression, washing

  • filters, cyclones, electrostatic, magnetic

  • selective flotation

  • selective extraction to a second liquid phase
    .. emulsion, coated wire / drum

  • selective capture on a solid surface
    .. second powder, wire, sheet Separation from Solids of Differing Composition

  • by Size Classification
    .. screens, cyclones, etc Dispensing and Distributing Solids (on top of another phase)

  • sifters, sprayers, settlers, electropinning

  • suspension coaters, spin coaters, electrocoaters

  • adhesion strength, binders

6. Thermal interactions in Particles

  • Radiant Energy Exchange at Dilute and Dense Loadings
  • Thermal Conduction in Packed Beds
  • Thermal Transfer from the Fluid Phase
  • Mixing Hot and Cold Particles
  • Wall - Bed Heaters (Screw, Plate)
  • thermophoresis
  • sintering, glass-crystal, melting, freezing, evaporation
  • drying, condensation, adsorption, stripping

7. Chemical Interactions in Particles

Particle-Solute Interaction

  • Surface Chemistry
  • Effect of the Surface on Attraction / Repulsion
  • Surface Thermodynamics, Microcalorimetry
  • Adsorption, Quantifying Its Rate and Extent
  • Polymer Thermodynamics
  • Entropy and Steric Effects
  • Dispersants, Flocculants, Wetting Agents
  • Cohesion, adhesion, impurity-diffusional sintering, agglomeration Reactivity of Fine Powders
  • significance of large area and small particle separation
  • combustion
  • evaluation and control of dust explosion hazards
    .. test methods
    .. vent panels, crushable environment
    .. inerting and suppression measures

  • evaluation and control of run-away slurry reactions
    .. test methods
    .. quenching and discharge to thin film area

  • tribocharging, mechanochemistry, optical trapping Water - Very Special Stuff

  • Gross, Loose, Wicked, Adsorbed, Bound

  • Rheology as Moisture Increases (sand, silica spheres, Teflon fluff)

  • Drying, dryer selection, case hardening
    .. vacuum drying, phase displacement, supercritical

8. Mathematical Techniques for Particulate Systems

MATHEMATICAL TECHNIQUES Modeling and Simulation Techniques

  • CFD, DEM, FEM, etc.
  • single particle physics (breakage)
  • bulk powder (compaction)
  • electrostatic interaction
  • scattering (light, sound)
  • chemical speciation and phase equilibria
  • polymer conformation statistics
  • slurry rheology

9. Health, Safety, and Environmental Concerns

Health Implications of Particulates

  • inhalation
  • ingestion
  • adhesion effects
  • effects on the eye Safety Implications of Particulates
  • overflow due to excessive foaming
  • inoperative instrumentation due to sediment, foam, or dispersions
  • failure to flow due to high loading of particulates
  • valve, blade, and wall erosion
  • pipeline plugs from siltation or jamming
  • presure buildup from screen or filter blinding
  • runaway thermal reactions and explosions Environmental Implications of Particulates
  • albedo of the earth
  • penetration of light into the ocean
  • siltation
  • entropy and mineral resources
  • inactive dust impact on leaf and lung functions
  • spread and effect of toxic dusts (lead, etc)
  • aerosol effect on greenhouse gases

10. Specific Applications of Particle Technology

Specific Industrial Operations

  • recovery of fines
  • water clarification
  • sewage treatment
  • coal compustion
  • pharmaceutical pill compaction
  • stack gas cleanup

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URL: http://www.erpt.org/outline.htm

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