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Section II Bulk Material Basics and Their Influence on Equipment Selection Sharon Nowak K-Tron Global Business Development Manager, Food and Pharmaceuticals.

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Presentation on theme: "Section II Bulk Material Basics and Their Influence on Equipment Selection Sharon Nowak K-Tron Global Business Development Manager, Food and Pharmaceuticals."— Presentation transcript:

1 Section II Bulk Material Basics and Their Influence on Equipment Selection Sharon Nowak K-Tron Global Business Development Manager, Food and Pharmaceuticals

2 Agenda Session I - Corporate Introduction Session II - Bulk Materials Basics (K-Tron) Session III - Pneumatic Conveying Technology and Product Overview (K-Tron) Session IV – Feeding Technology and Product Overview (K-Tron) Session V – Advances in Twin Screw Compounding (Coperion) Session VI (Coperion) Session A: Food Extrusion on Twin Screw Extruders Session B: New Developments in the Compounding of Plastics Session VII (K-Tron) Session A: Selecting the Right Feeder for Food/Pharmaceuticals Session B: Selecting the Right Feeder for Plastics Session VIII Pneumatic Conveying (K-Tron) Session A: Pneumatic Conveying Systems for Food/Pharmaceuticals Session B: Pneumatic Conveying Systems for Plastics

3 Moist, sticky materials Friable materials Large particles Blends or Masterbatch Abrasive materials Non-Free Flowing products Free-flowing materials Contamination Sensitive Products Materials that Fluidize or liquefy Products that pack, plug, cake or smear Hazardous materials Bulk Solids Definition

4 Where do they come from? Organic Cocoa Powder Flours Sugar Inorganic Calcium carbonate Titanium dioxide Silica

5 Flowability Influencers

6 Material Characteristics & Tests TestProperty MeasuredAffects… Bulk Density Loose & Compact ρ = Weight per unit of volumeStorage vessels size & materials compressibility Particle ShapeParticle geometryDischarge from hoppers Particle Size & PSDAspect ratio (L/D)Flowability & Compressibility Particle HardnessScratch-ability, hardness, abrasionAbrasiveness on equipment. Type of metal and surface treatment used for pipes, bins, hoppers, screws. Particle fragility. Moisture Content% of water in the materialCohesive strength & arching ability of bulk materials PermeabilityAbility of the air to pass through bulk materialAbility to flood CompressibilitySensitivity of the material to pressureTendency to pack in a feeder hopper CohesivenessTendency of material to adhere to itselfMinimum outlet diameter for bins, hoppers, and outlets

7 Material Characteristics which contribute to poor flowability High Aspect Ratio Wide PS & PSD Compressibility and Cohesiveness

8 Bulk Densities Comparison Compacted (CBD) Loose (LBD) Aerated (ABD) 10%

9 Loose Bulk Density (LBD) Mass per volume of loose powder, gm/cm 3 In Carr series of measurements, a sieve with a mesh size greater than D100 of sample is used to control the flow of the material being analyzed. 100 CC Sieve Funnel Sample Slide courtesy of Hosokawa Micron Powder Systems, Summit, NJ

10 Tapping Unit Packed or Compacted Bulk Density (CBD) Mass per volume of packed powder, gm/cm 3. In Carr Series of measurements, fill container to top of retainer wall, typically the same size as the cup. Tapping Unit raises and drops container automatically. Carr Standard: 18 mm 180 taps 100 CC Sieve Funnel Retainer Sample Slide courtesy of Hosokawa Micron Powder Systems, Summit, NJ

11 Bulk Density Affects…

12 Inorganic: Bulk Density of Calcium Carbonate LBD 0.3 g/cm 3 CBD0.4 g/cm 3 LBD1.38 g/cm 3 CBD 1.47 g/cm 3 CaCO 3 (95% pure)CaCO 3 (99% pure)

13 Organic: Bulk Density of Sugars LBD.88 g/cm 3 CBD1.06 g/cm 3 LBD.68 g/cm 3 CBD.95 g/cm 3

14 Particle Shape Aspect Ratio

15 Sample Sieve Analysis of Powdered Sugar

16 Particle Size Code A Code C Code B

17 Particle Size & PSD % Passing Particle Size (mm) Sieve Number /43 1/ Broad Distribution Narrow Distribution Top Cut d50

18 Particle Hardness

19 Hardness Methods Rockwell Brinell Vickers Knoop Shore Mohs Barcol Mineral name Hardness (Mohs) Hardness (Vickers) kg/mm 2 Graphite1–2VHN 10 =7–11 Tin1½VHN 10 =7–9 Bismuth2–2½VHN 100 =16–18 Gold2½VHN 10 =30–34 Silver2½VHN 100 =61–65 Chalcocite2½–3VHN 100 =84–87 Copper2½–3VHN 100 =77–99 Galena2½VHN 100 =79–104 Sphalerite3½–4VHN 100 =208–224 Heazlewoodite4VHN 100 =230–254 Carrollite4½–5½VHN 100 =507–586 Goethite5–5½VHN 100 =667 Hematite5–6VHN 100 =1,000–1,100 Chromite5½VHN 100 =1,278–1,456 Anatase5½–6VHN 100 =616–698 Rutile6–6½VHN 100 =894–974 Pyrite6–6½VHN 100 =1,505–1,520 Bowieite7VHN 100 =858–1,288 Euclase7½VHN 100 =1,310 Chromium8½VHN 100 =1,875–2,000

20 Particle Interactions… Particle – Particle Van de Waals Forces Electrostatic Forces Capillary Forces Sintering Forces Collisions Particle – Equipment Friction Shear Strength Particle – Environment Humidity Temperature Permeability Vibration Time

21 Moisture Content Increase cohesiveness Inter-particle liquid bridge formation Substantial effect on frictional properties of materials

22 Particle – Particle Interactions Capillary ForcesSintering Process Liquid Bridges! Solid Bridges! F c = 2πRγ ε n = kt R

23 Particle – Particle Interactions F νω = AR / 12a 2 F νω = hŵ 1+ hŵ__ 8πa 2 8πa 2 H F νω =1 to 10eV (most solids) Gravity Defiance! van der Waals Forces

24 Particle – Equipment Interaction Friction Internal Solid particles flowing against each other Angle of internal friction Wall Solid particles sliding along a surface Wall friction angle V = K ΔФΔФ A σAσA ζAζA FRFR

25 Particle – Equipment Interactions

26 Particle – Environment Interactions

27 Time Consolidation Increase in strength when stored at rest under compressive stress for a long time interval Sintering Plastic deformation at particle contacts Interactive Forces! σvAσvAσcAσcA

28 Stresses in Bulk Solids Not a Newtonian Fluid! Shear stresses can be transmitted even at rest Shear stresses are different in different cutting planes State of stress in a bulk solid cannot be completely described by a single numerical value Compressibility Cohesion X Y Z dy dz dx σ zz ζ zy ζ zx ζ xz ζ xy σ xx ζ yz σ yy ζ yx σ = Stressζ = Shear

29 Permeability Ability of gas to pass through the material

30 Gas Permeability A measure of how easily gas flows through standing material Relates to particle size, shape, and density Why is important? Tendency for the bulk material to fluidize or flood Pellets have high gas permeability and thus dont easily flood Fine fumed silica has poor gas permeability thus will flood easily as the sub-micron, light weight particles become entrained in the air stream

31 Compressibility The ability of the powder to be compressed within a specified container (NOTE: Carr used a 100 cc container The value is determined by calculating subtracting the Aerated from the Packed Bulk Density Measurements. 100 x ( Packed - Aerated ) Packed Bulk Density = % Compressibility Slide courtesy of Hosokawa Micron Powder Systems, Summit, NJ

32 Additional Laboratory Tests Angle of Repose Poured Angle Angle of Spatula Can Velocity Terminal Velocity Bulk Velocity Fluidizability Conveyor Equipment Manufacturers Association Guidelines CEMA Standard 550, March 26, 2009

33 Angle of Repose PE pelletsShredded PS Sugar Cycloserine

34 4.5 m. Added Height 58 cm. 3.9 m. 3 m. Dia. 22 cu.m. 4 cu.m. 26 cu.m. 2 cu.m. Water Fill Volume of this bin 28 cu. m. Water Fill Volume of this bin 33 cu. m. Angle of Repose (loose) Intro here picture of pile With angle of repose Convert all these to metric

35 Can Velocity Can Velocity –the gas velocity within a specific area Can Vel = CFM/ABH CFM = Gas volume ABH = Cross sectional area (of receiver housing, bag house, etc) Interstitial Velocity – The apparent velocity of a gas as it passes by a filter bag matrix. It is found by dividing the collector gas volume by its cross sectional area, after the cross sectional of the bags have been subtracted from the collector cross sectional area.

36 Below 100 FPM Can Velocity

37 Kinematic Angle of Surface Friction Particle to Wall Friction Pressure or Force Kinematic Angle of Friction F F

38 Loose Drained Angle Calculate the volume of the inverted cone created during discharge. Determine silo effective usable space, from low level signal Determine where the low level indicator should be located Usable refill area. Placement of low level indicator.

39 Four Basic Categories of Flow Types Floodable When mixed with air/gas become highly charged like a fluid Difficult to handle. Flows freely Flows across conveyor belts and screws faster than the speed Cohesive Compressible material. Packs easily Sticky Hygroscopic Easy flowing Free-flowing. Does not stick together Uniform particle size and shape Does not absorb air/gas and become fluidized Difficult flowing Material tends to mat together (strings) Non-uniform particle size and shape Fragile Coarse or abrasive

40 Over the years, in an effort to reduce human subjectivity while performing the Carr methods, instruments have gone from strictly manual to computer assisted operation. Powder Tester for Flowability Slide courtesy of Hosokawa Micron Powder Systems, Summit, NJ

41 Flowability as per the Ralph Carr series of Indices 41 Slide courtesy of Hosokawa Micron Powder Systems, Summit, NJ

42 Floodability as per the Ralph Carr series of Indices 42 Slide courtesy of Hosokawa Micron Powder Systems, Summit, NJ

43 Summary: General Scale of Flowability Flow CharacteristicCompressibility Index (%) Hausner Ratio Excellent – 1.11 Good – 1.18 Fair – 1.25 Passable – 1.34 Poor – 1.45 Very Poor – 1.59 Very, very poor> 38> 1.60 Source: Carr. R.L. Evaluating Flow Properties of Solids. Chem. Eng. 1965, 72, 163 – 168

44 Questions?

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