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7/22/2019 FTNW08-Heimann ppt
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Advantages and Disadvantages in
Particle Size Reduction Techniques
Mark HeimannApplications ManagerRoskamp Champion
2975 Airline CircleWaterloo, Iowa 50703 USATel +1 319 232 8444Fax +1 319 236 0481
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Why Particle Size Reduction?
Increased Surface Area
Expose to heat, moisture, enzymes Increased Digestibility and Palatability
Reduced Sorting & Selective Feeding Preparation for Secondary Operations
Mixing Pelleting & Extrusion
Handling & Conveying
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Roller Mill Ground Corn Hammermill Ground Corn
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Particle Shape and Texture
Roller Mill and Hammermill
Roller Mill Particle Attributes:
Elongated, Sliver or FlakeLike
Rough Edges
L/D Ratio of 1.87
Lower Bulk Density
Hammermill Particle Attributes:
Spherical, Cubic ShapedParticles
Smooth, Polished Edges
L/D Ratio of 1.4:1
Higher Bulk Density
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Surface Area Comparison
Roller Mill
908 mean particle diameter
55 cm/gm calculated surface area
1281 cm/gm measured surface area
Hammermill
962 mean particle diameter
68 cm/gm calculated surface area 1217 cm/gm measures surface area
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Particle Size vs Cost to Produce
Grinding U.S. #2 Yellow Corn
100 200 400 600 800 1000 1200 1400 1600 1800 2000
Aquaculture----Chicks--Pigs-Chickens---Turkeys-------Cattle
0
0.2
0.4
0.6
0.8
1
1.21.4
1.6
$/Ton
toGrind
Roller Mill Hammermill
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Roller Mill and Hammermill
Roller Mill
Roll Corrugations
Fast Roll Speeds
Differential Roll Speeds
Feed Rate
Motor Load
Roll Spacing
Hammermill
Tip Speed
Screen Hole Size
Hammer Pattern and Position
Feed Rate
Motor Load
Fixed Operating Parameters
Variable Operating Parameters
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Roller Mill or Hammermill?
Cracking, Crimping,Minimum Fines, Dust
Coarse Grinding,Textured Feeds
Grinding for PelletingCorn, Wheat, Milo
Grinding for PelletingOats, Barley, Fiber
Rendering ApplicationsWood, Hulls, Etc.
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Roller Mill Advantages
Energy Savings
More tons processed per kWh Savings range from 15-85% or more
Product Quality
More uniform, less fines & oversize particles Less heating
Roller Mill 0-3 , Hammermill up to 10
Less moisture loss Roller mill < %, Hammermill 1-3% typical
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Roller Mill Advantages
Less Noise, Less Dust
Better work environment Reduce safety hazards
No Aspiration Required
Reduces connected HP & space required
Less auxiliary equipment to maintain
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Efficiency Comparison on Corn
Roller Mills and Hammermills
350 400 450 500 600 700 800 900 1000
Mean Particle Size - Microns
0
200
400
600
800
1000
1200
Efficiency - #/H.P.-HR
HM DP TP
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Ground Corn
Roller Mill and Hammermill - 700 Microns
4 6 8 10 14 20 30 40 50 70 100 140 200 270 Pan
U.S. Sieve
0
5
10
15
20
25
30
35Percent On
Roller Mill - 712
Hammermill - 708
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Roller Mill Disadvantages
Works best on easy to grind materials
Corn, cereal grains, extracted meals Not effective on fiber, two dimensional products
Heavy machine
Additional bearings & drives Rolls are heavy
Equipment needed for routine roll change
Additional operator inputs required Adjust rolls to suit grind requirements
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Typical DP Roller Mill
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Match Corrugations to Products / Sizes
Coarse corrugations for large products andcoarse products
High capacity, long life
Fine corrugations for small products, finefinished particle size
Lower capacity, fewer tons before recorrugation
Optimizing the Roller Mill System
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Finished Particle Size / Corrugations
Roller Mills
4 5 6 8 10 12 14 16 18 20 22 24 30 Smooth
Corrugations
0
1
2
3
4
Me
anParticleS
ize-Micronsx1000
Min Max
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Equipping the System
Two or Three pair high machines for grinding Fine grinding
Multiple products
Differential Drives Improves grinding efficiency
Finer grinds possible, better product consistency
Rolls must be properly adjusted
In Tram and Parallel
Optimizing the Roller Mill System
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Annual Operating Costs
Roller Mill and Hammermill
Grinding 32,000 Tons of corn annually
3.264
7.36
10.368
14.4
Roller Mill - 1200
Hammermil l - 1200
Roller Mill - 600
Hammermill - 600
0 2 4 6 8 10 12 14 16 18
$ X 1000Maintenance Electrical
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Hammermill Advantages
Easy to Use Select screen size
Turn it on
Versatile
Process a wide range of materials Grain, High fiber, High protein
Can be set up for very fine grinding (90%-60 mesh)
Must be configured per application
Hammermills are generally understood
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Hammermill Disadvantages
More expensive to operate High energy cost
Lower product quality More oversize bits, more fines Heating of product drive off moisture
Condensation in bins and ductwork Poor material flow characteristics
Many hammermills vibrate and are noisy
Risk of fire/dust explosion
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Typical HM Hammermill
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PrimaryDestruction
Zone
Acceleration Zone
FullHammerTipSpeedZone
Contact Point
"Regrind Chamber"
"Flow Director"
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Annual Operating CostsHammermill - Good vs. Poor Maintenance
Grinding 32,000 Tons of corn annually
14.4
18.56
$0.05/Ton
$0.02/Ton
0 5 10 15 20 25
$ X 1000Maintenance Electrical
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Optimizing Hammermill Performance
Designing the System
Tip Speed Screen Area
Hammer Pattern
Hammer Position
Feeder
Takeaway System
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Optimizing Hammermill Performance
Match Tip Speed and Screen Hole Size
Use high tip speeds for fine grinding, highfiber, and tough to grind materials
>90 M/Sec
Screens 3 mm and smaller
Use low tip speeds for coarser, more uniformfinished products
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Tip Speed vs. Particle Size
38" , 44", and 54" @ 1800 RPM
1.6 2.5 3.2 4 5
Hammermill Screen Size in mm
0
200
400
600
800
1000
1200
Mean Particle Size - Microns
54" Hammermill 44" Hammermill 38" Hammermill
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Tip Speed vs. Efficiency38", 44", and 54" @ 1800 RPM
1.6 2.5 3.2 4 5
Hammermil l screen size mm
0
100
200
300
400
500
600
Efficiency #/HP-HR
38" Hammermill 44" Hammermill 54" Hammermill
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Hammermill Tip Speeds
Model Diameter 1200 1500 1800 3000 3600
Viking 16 NA NA NA 64 76
Challenger 22 NA NA 52 88 105
Impactor 28 NA 55 66 111 NA
Standard 38 60 76 91 NA NA
Magnum/HM 44 70 87 105 NA NA
Intl Magnum 54 86 111 NA NA NA
HM High Speed 54 86 111 129 NA NA
Motor RPM
Tip speed in Meters per Second (M/Sec)
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10 to 20 In/HP Typical Range 85 to 170 cm/kW
12 to 16 In/HP for grain and easy to grind 100 to 140 cm/kW
14 to 20 In/HP for high fiber, tough to grind 120 to 170 cm/kW Less In/HP increases heating & moisture loss
Less In/HP produces finer grind More In/HP increases capacity & efficiency
Ideally screen open area is >4 In/HP (35 cm/kW)
Hammermill Screen Area
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Hammermill Screen Area
Length x Width x N = Screen area (In2) Use 14 In/HP typical (120 cm/kW)
Up to 12 to14 In/HP for finer grinding
100-120 cm/kW
Use 2.5 to 3.5 In of open area per HP for finer finishedproducts (20 to 30 cm/kW)
Excessive power/In can create problems
Excess product heating
Loss in efficiency Excessive screen wear and damage
Leakage at screen sealing areas
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Hammer Pattern
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Hammer Position
Coarse position for pre grind Clearance is 7/16 (11-12 mm)
Fine position for final grind Clearance is 7/32 (4-5 mm)
8 and 12 pin all fine rotors available
Hammer Position
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Coarse positionis further from
screen
Fine position is
closer to screen
Hammer Position
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Hammermill Feeders
Rotary Pocket Feeders are preferred
Even feeding across mill width Easy to automate
Available with self cleaning magnet
Some materials require a Screw Feeder
Less uniform distribution
Rotary Pocket Feeder
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Rotary Pocket Feeder
Air Assist with Screw Conveyor
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Air Assist with Screw Conveyor
Step Grind System with Single Pair Roller Mill
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Raw materials in, grain,
pellets, meal
Roller Mill, initial reduction
Hammermill, secondary grinder
Finished, ground meal, to further processing
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Step Grind System with SP Roller Mill and HM Hammermill
Advantages of Roller Mill/Hammermill
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Advantages of Roller Mill/HammermillStep Grinding System (Primarily Grain)
Greater efficiency lower energy cost
Lower cost, longer life wear parts
Larger diameter, thicker screens
Increased hammer l ife for final grinder (up to 3 times)
Increase hammermill capacity (30-50%)
Disadvantages of Roller Mill/HammermillStep Grinding System
Increased capital costs
Increased space requirements
More complicated to operate and maintain
Advantages of Roller Mill/Hammermill
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Advantages of Roller Mill/HammermillStep Grinding System (Primarily Grain)
Greater effic iency lower energy cost
Lower cost, longer li fe wear parts
Larger diameter, thicker screensIncreased hammer li fe for f inal grinder (up to 3 times)
Increase hammermill capacity (30-50%)
100 HP Hammermil l, 3mm screen on corn will achieve
600 @ 12 MTH, $0.31/ton electrical + $0.04/ton parts = $0.35/ton
15 HP Roller Mill + 100 HP Hammermil l, 5 mm screen on corn will achieve
600 @ 16 MTH, $0.26/ton electrical + $0.04/ton parts = $0.30/ton
33% increase in capacity and 15% reduction in grinding cost
Champion Dedicated Fine Grind Hammermills
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Champion Dedicated Fine Grind HammermillsProduction Capabilities
Model HP Screen Area Capacity
90%-500 90%-250
HM54-16 150 2350 In(1.5 M) 4.0-5.0 MTH 2.0-3.0 MTHHM54-24 250 3530 In(2.3M) 5.5-6.5 MTH 3.0-4.0 MTH
HM54-32 350 4700 In(3.0M) 9.0-10.0 MTH 5.0-6.0 MTH
HM54-40 400 5880 In(3.8M) 11.0-12.0 MTH 6.0-7.5 MTH
HM54-48 500 7050 In(4.5M) 14.0-15.0 MTH 8.0-10 MTH
Actual finished particle sizing and hammermill capacity will vary depending on the feedformulation and raw material conditions (protein, moisture, temperature, fat content,etc.), aspiration air flow, and the condition of the wear parts within the hammermill. Thefigures indicated above reflect typical feed formulations used to produce extruded petfoods (90%
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Champion Dedicated Fine Grind HammermillsOperation and Maintenance Costs
Size range 90%
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AVRHM
AVRHM Ad antages
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AVRHM Advantages
Relatively Easy to Use
Select screen
Turn it on
Coarse textured grinds
Compared to other hammermills
Ease of screen and Hammer Change
No Aspiration Air Required
AVRHM Disadvantages
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AVRHM Disadvantages
High Temperature Material Discharge* Roller Mill
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AVRHM Disadvantages
Summary of Testing Betagro Northern 01/07
Buhler AVRH 2x110 kW motors 6 trials, 520, 2.406 Dgw, 26 MTH, 8.5 kW/ton
2.5 and 3 mm screens
Champion HM54-40 1x315 kW motor
6 trials, 385, 2.344 Dgw, 40 MTH, 7.9 kW/ton
3 mm screens
Air Swept Pulverizers
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p
Air Swept Pulverizers
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p
Air Swept Pulverizer Advantages
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Air Swept Pulverizer Advantages
Relatively Easy to Use
Select screen and/or grinding elements
Turn it on
Very fine grinds achievable
Built in Air Classifiers
Control finished particle sizing
Ai S t P l i Di d t
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Limited to Very fine grinding
High Aspiration required
High moisture loss
Higher cost Initial equipment cost
Operating costs Electrical costs can be > $5.00/ton Parts cost can be > $0.50/ton
High noise level generation Complicated machines & systems
Air Swept Pulverizer Disadvantages
Di Mill
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Disc Mills
Di Mill
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Disc Mills
Disc Mills / Attrition Mills
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Generally Low Capacity 75 HP (55 kW) maximum connected power
Replacement parts are specialized Limited availability single source supply
Compromise between roller mills and
hammermills More noise & fines than roller mill Less noise & fines than hammermill
Limited effectiveness on fibrous materials Little data available for comparison
Disc Mills / Attrition Mills
Chinese Vibrating Screen Hammermill
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Chinese Vibrating Screen Hammermill
Chinese Vibrating Screen Hammermill
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Chinese Vibrating Screen Hammermill
Low Output/kW when like products are produced 1200 VSH
600 Conventional Hammermill Additional mechanism
Screen vibrators
Additional wear Very little data available for comparison
Energy consumption vs particle size
Maintenance cost/ton Installed cost, aspiration requirements, etc.