Bulk Solids: Science / Engineering / Design!
Ways to Minimise
Particle Attrition
Carrie Hartford
Senior Engineer
chartford...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
2
Outline
„ Discuss causes and effects of pa...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
3
What is attrition?
“Rubbing away or
wearing...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
4
Other terms
Degradation - Decline to a lowe...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
5
Attrition is a concern in virtually every
i...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
6
Effects of particle attrition
„ Increased ...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
7
Effects of particle attrition
„ Increased ...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
8
Effects of particle attrition
„ Increased ...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
9
Effects of particle attrition
„ Increased ...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
10
Effects of particle attrition
„ Increased...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
11
Effects of particle attrition
„ Increased...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
12
Factors that affect particle attrition
„ ...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
13
System review
Attrition mechanisms
„ Impa...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
14
System review
Attrition mechanisms
„ Comp...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
15
System review
Attrition mechanisms
„ Shea...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
16
System review
Attrition mechanisms
„ Comp...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
17
Attrition tests
„ Impact
„ Hopper flow
„...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
18
Attrition tests
- impact
„ Used to evalua...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
19
Attrition tests
„ Impact
„ Hopper flow
„...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
20
Attrition tests – hopper flow
- rotational...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
21
Attrition and shear strain
+16 +20 +30 +35...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
22
Attrition tests
„ Impact
„ Hopper flow
„...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
23
Attrition by Compression!
Principle Pressu...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
24
Attrition / friability tests - particle ha...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
25
Attrition tests
„ Impact
„ Hopper flow
„...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
26
Engineered solutions
„ Can you change the...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
27
Engineered solutions
„ Transfer chutes
„...
Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN
28
Summary
„ The effects of particle attriti...
Bulk Solids: Science / Engineering / Design!
Questions?
Carrie Hartford
Senior Engineer
chartford@jenike.com
08 9277 3303
...
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Carrie Hartford - JENIKE & JOHANSON PTY LTD - Ways to minimize particle attrition that can generate explosive dust

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Carrie Hartford delivered the presentation at the 2014 Dust Explosions Conference.

The 2014 Dust Explosions Conference examined industrial hazards, the means to control or eliminate dust and analysed the latest technology to ensure the maximum protection and safety of organizations. The event also featured recent industrial case studies and new safety recommendations.

For more information about the event, please visit: http://www.informa.com.au/dust14

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Carrie Hartford - JENIKE & JOHANSON PTY LTD - Ways to minimize particle attrition that can generate explosive dust

  1. 1. Bulk Solids: Science / Engineering / Design! Ways to Minimise Particle Attrition Carrie Hartford Senior Engineer chartford@jenike.com 08 9277 3303 Perth WA
  2. 2. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 2 Outline „ Discuss causes and effects of particle attrition with granular products „ Evaluate where most of the dust is generated „ Characterize material’s attrition behavior through various attrition tests „ Engineer solutions to reduce dust generation
  3. 3. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 3 What is attrition? “Rubbing away or wearing down by friction” “Gradual diminution in number or strength because of constant stress” Example – bisphenol
  4. 4. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 4 Other terms Degradation - Decline to a lower condition, quality or level. Usually associated with changes in chemical or physical condition Friability - tendency to readily crumble; brittle
  5. 5. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 5 Attrition is a concern in virtually every industry „ Chemicals, plastics „ Foods „ Pharmaceuticals „ Power generation „ Metals „ Detergents
  6. 6. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 6 Effects of particle attrition „ Increased dust levels – safety hazard
  7. 7. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 7 Effects of particle attrition „ Increased dust levels – safety hazard „ 281 combustible dust fires and explosions in industry between 1980 and 2005 causing 119 fatalities and 718 injuries in the USA alone „ Investigation performed after 3 catastrophic dust explosions killed 14 workers in 2003. „ Secondary dust explosions, due to inadequate housekeeping and excessive dust accumulations, caused much of the damage and casualties in recent catastrophic incidents. “Investigation Report – Combustible Dust Hazard Study”, US Chemical Safety and Hazard Investigation Board. November 2006
  8. 8. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 8 Effects of particle attrition „ Increased dust levels – safety hazard „ Flow stoppages (arching, ratholing)
  9. 9. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 9 Effects of particle attrition „ Increased dust levels – safety hazard „ Flow stoppages (arching, ratholing) „ Caking
  10. 10. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 10 Effects of particle attrition „ Increased dust levels – safety hazard „ Flow stoppages (arching, ratholing) „ Caking „ Off-spec product – too fine or too lumpy
  11. 11. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 11 Effects of particle attrition „ Increased dust levels – safety hazard „ Flow stoppages (arching, ratholing) „ Caking „ Off-spec product – too fine or too lumpy „ Increased segregation
  12. 12. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 12 Factors that affect particle attrition „ Particle hardness „ Particle shape and size „ Energy of particle impact „ Surface impact „ Particle bed impact „ Compression „ Shear „ Surface hardness and roughness „ Particle chemistry „ Propensity to melt or smear !
  13. 13. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 13 System review Attrition mechanisms „ Impact „ Particles shatter „ Occurs when material stream is redirected „ Examples „  Drop onto pile „  Drop into bin „  Belt-to-belt transfer chute „  Bends/diverters in pneumatic conveying line
  14. 14. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 14 System review Attrition mechanisms „ Compression „ Failure along weak planes „ Examples „  Bin/silo „  Railcar „  Pinch point in feeders
  15. 15. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 15 System review Attrition mechanisms „ Shear „ Edges of particles chipped off or worn away „ Examples „  Interparticle motion „  Sliding along bin wall „  Cyclone travel
  16. 16. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 16 System review Attrition mechanisms „ Compression and shear „ Examples „  Converging flow channel „  Mechanical feeder (especially screw feeders)
  17. 17. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 17 Attrition tests „ Impact „ Hopper flow „ Compression „ Pneumatic conveying
  18. 18. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 18 Attrition tests - impact „ Used to evaluate particle attrition during filling of silos, hoppers, and chutes
  19. 19. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 19 Attrition tests „ Impact „ Hopper flow „ Evaluate particle attrition due to funnel or mass flow in a hopper Flowing! Stagnant! Funnel Flow! Mass 
 Flow!
  20. 20. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 20 Attrition tests – hopper flow - rotational shear
  21. 21. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 21 Attrition and shear strain +16 +20 +30 +35 +40 +50 +70 +100 Pan -4 -3 -2 -1 0 1 2 3 4 Change in percentage after test Mesh sizes Changeinpercentage
  22. 22. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 22 Attrition tests „ Impact „ Hopper flow „ Compression „ Evaluate particle attrition due to loads acting on particle or bed
  23. 23. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 23 Attrition by Compression! Principle Pressure, psf! PercentMinus2.5mm!
  24. 24. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 24 Attrition / friability tests - particle hardness
  25. 25. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 25 Attrition tests „ Impact „ Hopper flow „ Compression „ Pneumatic conveying „ Measure particle size before and after conveying
  26. 26. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 26 Engineered solutions „ Can you change the material? „ Increase particle hardness „ Decrease particle size „ Make particles rounded vs. angular or flaky „ Can you change the handling equipment?
  27. 27. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 27 Engineered solutions „ Transfer chutes „ Control the flow of material „ Minimise drop heights „ Bins/hoppers and feeders „ Evaluate the appropriate flow method to minimise attrition „ Pneumatic conveying systems „ Minimise conveying velocities „ Streamline the layout to minimise bends „ Consider dense phase vs. dilute phase conveying „  Dense phase is not suitable for all materials
  28. 28. Bulk Solids: Science / Engineering / Design!SCIENCE ⏐ ENGINEERING ⏐ DESIGN 28 Summary „ The effects of particle attrition can be costly „ Increased dusting „ Powder caking „ Decreased product performance „ Creation of safety hazards such as dust explosions „ Particle attrition can be minimised through proper engineering „ Attrition tests „ Change the material and/or change the equipment
  29. 29. Bulk Solids: Science / Engineering / Design! Questions? Carrie Hartford Senior Engineer chartford@jenike.com 08 9277 3303 Perth WA
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