FTNW08-Heimann ppt

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

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


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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Air Swept Pulverizers


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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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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.

Documents

FTNW08-Heimann ppt