feed technology - bogor agricultural...

11/13/2013

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Prof. M. Eeckhout

November 18th 2013

Feed Technology

Introduction in Feed Technology

content

1. Introduction

2. Mixed feed: raw materials

3. Delivery and storage

4. Dosing and weighing

5. Milling

6. Mixing

7. Pelletizing

8. Cooling

9. Pellet quality


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1. Introduction

• Compound feed = Mixture of feed raw

materials, with or without additives, which

are intended for oral animal feeding as

complete or complementary feeding

stuffs

Large variety in raw materials

Nutritional data of raw materials is required

Information on nutritional needs per type of

animal


2. Mixed feed:

raw materials

• wheat • wheat bran

• wheat midling

• maize bran

• rice bran • rice polish • Rice straw

• Cassava • Sweet patatoe

• fish meal • haricot bean


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2. Mixed feed:

raw materials

• Oil by products – cotton seed cake – groundnut cake – linseed cake – sesame seed cake – palm kernel cake – soybean meal – sunflower cake

• Cane sugar byproducts – Sugar cane top – Molasses


By products from food industries

2. Mixed feed:

raw materials

• brewer's grain • Starch byproducts – sweet potato stem and leaves – casava byproducts


By products from food industries

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2. Mixed feed:

raw materials

– Mixture of specific feed ingredients: minerals, trace elements, vitamines, enzymes …with a carrier (wheat middlings, …) to be added to a compound feed (2% to 5%)


Premixes


Delivery

Hammermill weighing

Pelletising

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3. Delivery and

storage

• Transport:

– Own or contracted

– Rail or land

– Bulk or packed

• Clean vessels, protected against pests,

water,….

• Control upon delivery: first step to ensure

quality and safety of the end product


3. Delivery and

transport

Internal transportation systems:

• gravitation runways;

• scraping conveyor;

• bucket conveyor;

• pneumatic conveyors with sucking,

pressing or combined types.


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Bucket conveyor


solution for vertical transport

gentle product treatment

belt or chain bucket conveyor

with a capacity of 5 to 1,000 m³/h,

1,5 - 3 m/s

normal, stainless or special steel

design

coarse, fine-grained and powdery

bulk materials are powerfully and

flexibly conveyed.

closed system

Dust free

Bucket conveyor


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Scraper conveyor A scraper conveyor is a type of flight

conveyor.

It consists of a trough in which a

continuous driven chain with flights

(scrapers) is running.

The flights are scraping the material

over the bottom of the casing. T

he material is moving forward to the

discharge point (0.5-0.1 m/s)

The design is ideal for slower

transportation speeds over short

distances, on moderate inclines,

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Scraper conveyor

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Screw conveyors

highly versatile conveyor component

suitable for all kinds of bulk materials

Minimal space required due to its

extremely compact design.

dust-free environment due to a low

screw rotational speed and an enclosed

housing.

available in normal and stainless steel or

special steel in all diameters and lengths

deployed for vertical and horizontal

transport

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3. Delivery and

storage

• Storage :

– facilities should be free of chemicals,

fertilizers, pesticides and other potential

contaminants

– Feed products should be stored in such a way

that they can be identified easily and that

confusion with other products is prevented

– Any rejected products should be clearly

identified and held in segregated area


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Problems in bulk

storage


• Rat holes: when material clings or

builds up on the sides of the

vessel, creating a narrow flow

channel from top to bottom of the

vessel.

• Bridges occur when the material

arches over the discharge.

Material below the bridge will

discharge from the vessel creating

a void, while material above the

bridge is not able to discharge

• Blockages occur when the material

hardens together and obstructs

material flow at the discharge point

of the vessel.

• Bridges and blockages = no-flow

Problems in bulk

storage


• To avoid problems:

– Frequent cleaning – remove

bridge build up

– Low residence time – frequent

use of products

Do not store extremely large

amounts with poor use

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4. Dosing /

weighing

• Raw material are dosed according the

formula to be produced

dosing should be correct (small

tolerances)


4. Dosing /

weighing

• How and where products are weighed and

added

– Coarse raw material before milling

– Powders, premixes, medicated supplements

after milling

– Liquids (molasses, fat) on the mixer


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4. Dosing /

weighing

• How and where products are weighed and

added

– Coarse raw material before milling

– Powders, premixes, medicated supplements

after milling

– Liquids (molasses, amino acids) on the mixer


5. Milling

• Why ? – Good mixing and

homogeneity avoid segregation

– Increased digestibility

– Good pellet quality

• Excessive milling – Energy loss

– unnecessary wear on mechanical equipment

– Fines can harm the animal


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5. Milling


• Good mixing and homogeneity avoid

segregation

– It is impossible to mix protein, mineral, or

vitamin supplements and feed additives with

whole grain and have the material stay well

mixed from the mixer to the animals mouth.

– If whole grain is fed, mix the grain and

supplement together with silage to help keep it

together or use a pelleted supplement to

prevent separation.

5. Milling


• Increased digestibility

– The hull is a barrier, which is relatively

impermeable to rumen microorganisms and

digestive enzymes and must be broken by

either processing or chewing, otherwise much

of the useful nutrients in the grain will pass out

in the manure.

– Animals vary with respect to their ability to

break open the grain by chewing.

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5. Milling


Influence of milling on digestibility of grains

5. Milling


• Other benefits

– Processing can have either a positive or

negative effect on the palatability of grains.

– There is evidence that cattle fed whole grain

are more susceptible to bloat and digestive

upsets than those fed rolled grain and that

individual animal performance is much more

variable when whole grain is fed.

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5. Milling


• Read More

– Mathison et al. 1991a. Effect of feeding whole

and rolled barley in the morning or afternoon

in diets containing differing proportions of hay

and grain. J. Anim. Prod. 53:321-330.

5. Milling

-


The hammer mill

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The hammer mill

Velocity of hammers : 5000- 7000 m/min


The hammer mill


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5. Milling

Advantages of hammer mill :

• are able to produce a wide range of particle size

• work with any friable material and fibre

• ease of use

• low initial investment

• minimal maintenance needed

• particles produced using a hammer mill will generally be spherical, with a surface that appears polished.


5. Milling

Disadvantages:

• may generate heat (source of energy loss)

• particle size variability (less uniform)

• hammer mills are noisy and can generate

dust pollution


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5. Milling

• Parameters effecting capacity and efficiency

– Raw material: mais (corn) versus wheat

– Moisture content

– Fat content

– Size of screen perforation and screen surface

– Pressure (air flow)

– Hammer velocity

– Hammer and screen wear


5. Milling

- passing between two large steel

rollers

- least expensive

- the amount of fine particles in

feeds can be kept to a minimum

- Less flexible


The roller mill

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Evaluating particle size


• Bring 100 gramms of

product on a stack of

sieves

• From 2 mm pore size to

100 µm

• 5 minutes sieving time

• collect and weigh sieve

rest

5. Milling

Dsieve (mm)

Amount (g)

Percentage

residue

2 10 10

1,5 14 24

0,800 14 38

0,600 15 54

0,400 14 72

0,200 13 89

0 0 100

SUM: 100



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5. Milling


Control the amount

of fines


5. Milling

Fines should be avoided because they:

• Increase the risk of the onset of ruminal

acidosis

• Reduce palatability, increase sorting

• Increase feed refusals,

• May contribute to respiratory diseases. Read more:

De Nardi R. et al (2013) Effect of feeding fine maize particles on the reticular pH, milk

yield and composition of dairy cows

Journal of Animal Physiology and Animal Nutrition, Vol. 97 Issue 5


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Hammer wear

• Production capacity

decreases

• Replace before break

• Adequate maintenance


6. Mixing:

• Homogeneity depends on: – Particle size distribution

– Specific mass of particles

– Geometric form

– Electrostatic properties

• On the mixer : addition of liquids


Mixed feed : homogeneous mixture

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Type: horizontal mixer

Paddle Ribban


Types: vertical


• The screw agitator, turning on its axis, produces a lifting action

as it spirals the materials in an upward flow.

• At the same time, orbiting the tank, the screw removes material

away from the wall and deflects it into the centre of the tank.

• Material lifted by the screw gravitates downward, thoroughly

intermixing with material being spiraled upwards.

3 distinct intermixing actions

http://upload.wikimedia.org/wikipedia/commons/4/49/Paddle-Mixers-Logo.gif

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Type: vertical mixer


• The typical speed of the central screw is 70 to 80 Rpm.

• The Tip speed can fluctuate from 1 to 3 m/s.

• The result is most intimate intermingling of all

ingredients.

• The mixing time is depending on

– product characteristics,

– mixing accuracy

– batch size

Selecting a mixer


• Quantity to be mixed

• Mixing capacity versus mixing volume

– Paddle mixers – 15% minimal loading

– Ribbon mixers – 20 to 40 % minimal loading

• Mixing time (including loading and discharge

• Maintenance (including cleaning) cost

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Mixing homogeneity

Is determined by :

- Quantity to be mixed

- Mixing time – optimal mixing

- Mixing ration : 10% versus 0.1%


Measuring homogeneity

Homogeneity is measured by adding a tracer or

indicator product to the mixture.


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Measuring homogeneity

After certain time period, samples are analysed to

determine the concentration of tracer in the samples

Good homogeneity = low variation in concentration


7. Pelleting

Dosing, milling, mixing

Feed back

Conditioning

pelleting

cooling

Measuring pellet quality


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Advantages of pelletized feed

• No segregation possible

• Better intake

• Less odor

• Better flow

• Good weight/volume ratio

• Hygienic treatment

BUT: high investment and energy cost !


The pelleting process


This diagram shows the entire

pellet die with 2 roller shells

inside. This first picture shows a

ring die. Both the pellet die and

the roller shell are rotating, and

the rollers work to push the mixed

material through the holes of the

pellet die.

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. This diagram shows a close up

of the roller shell and a hole of the

pellet die. As the roll rotates it

compounds the raw material and

compacts/forces it into the hole of

the pellet die.



This diagram shows a close-up

cross section of a hole. The width

of the hole (in between the 2 grey

walls in the diagram) will be the

diameter of the finished pellets

that come out of the pellet mill.

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This diagram shows the hole on

the outer side of the pellet die.

Once the raw material is

compacted and force through the

holes of the pellet dies, the

formed pellets will come out from

the other side. Once cut be a knife

to a predetermined lenth, you will

be left with your finished pellets

ready for crumbling (optional) and

cooling.



The result is finished pellets.

Shrimp feed pellets, poultry feed

pellets, livestock feed pellets, fish

feed pellets, ….

Pictures from http://www.pelletdies.com/

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Steam (Vapour) Conditioning

• Mash parameters

before

– moisture 12 %

– temperature 30°C

• Mash parameters after

– moisture 15 tot 17 %

– temperature 65°C


Steam (Vapour) Conditioning

• Advantages

– better pellet quality,

– higher capacity,

– less wear

• Disadvantages;

– cost !

– Loss of temperature

unstable components


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Pelleting


Pelleting

• Die hole sizes usually range

from 1.5 mm (shrimp) up to

9.5 mm.

• Cattle 6 mm

• The thickness of the die

plate helps to determine the

compactness and stability of

the pellet. Pellet dies can be

up to about 90 mm thick


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Pellet die


Pellet roll

• Steel surface

• Surface with riffles

• Rotate at close

distance to the die

• Force feed mash

pass trough the die

holes

60

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8. Cooling (and

drying)

• Use of “cold” air

• Moisture 17-18% < 14% prevent mould

growth and loss of nutrients

• Temperature 65-85 °C 20°C

• Pellet hardening



8. Cooling (and

drying)

• Vertical cooler

– Counter flow

– < 14 % vocht

• Followed by sieving

to remove the fines

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• In the horizontal type of cooler/dryer the pellets

are conveyed on a perforated steel mesh or

moving belt through which a cooling air stream is

passed. The horizontal method is best for 'sticky'

dry pellets or for moist feeds


8. Cooling (and

drying)

9. Pellet quality

• Feed is too expensive to waste, so pellet quality has an

economic value.

• Customers require high product quality = acceptable

pellet stability, flowability or conveying behavior in

feeding systems and of course low costs.


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9. Pellet quality

• The requirement of high pellet stability – at the

same time meaning less fines

• Pellet stability is – besides shear strength and

hardness – normally defined by the abrasion

resistance.

• During handling (transport, storage, feeding)

only a minimum of fines is allowed to be formed.


9. Pellet quality

• There are a number of excellent methods to objectively measure and record the quality of pellets during the manufacturing process.

• This is the first step toward correcting destructive conditions and improving quality.

In literature : Pfost, Holmen, Pfost-Q-test, ligno tester all give different results


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pellet quality depends on

– 40% on formula

– 20 % on particle size

– 20 % conditioning

– 15 % die specifications

– 5% cooling/ drying

60% on formulation and

milling !


Abrasion resistance

Pfost test


Percentage of pellets that withstand abrasion

during mechanical and pneumatic

transportation

Holmen

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Hardness

how will the pellet

withstand pressure during

storage


University Ghent

Feed technologyLlab


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(left) Vertical mixer: inner

view

(up) Hammermill inner

view


Die and roll


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Steam addition control

unit


Measuring pellet

quality


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