The prosperity of industrial feed compounding is based on the refining effect of mixed and processed raw materials, especially since the introduction of the pelleting process in the 1920s.

1. Digital Re-print - July | August 2010
Factors affecting pelleting and energy consumption
Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom.
All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies,
the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of
information published.
©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form
or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872
www.gfmt.co.uk NEXT PAGE

2. Energy consumption Feature Feature Energy consumption
Table 1: Effects due to different feed processing measures
The original (primary) particle size is While formula- Short-term
Long-term
Effect conditioning Expanding Extruding
changed. tion and preparation conditioning
Factors affecting pelleting
and pelleting
This additional operating expense has to are beyond the press
be set in relation to less energy input during operator’s control, he Structure changes low no high very high
and energy consumption
milling. Commonly, the breakdown of energy is left with a number
Hygienisation low very high very high very high
consumption of compound feed production is of other parameters
Matrix changes low low high very high
60 percent for pelleting and about 16 percent to exercise influence
for milling (see Figure 3). on the pellet mill
by Rainer Löwe, Research Institute of Feed Technology Although these figures are not statistically operation and hence on the product quality. is reached when using small bore-hole diam-
of IFF, Braunschweig-Thune, Germany affirmed and based on feed producer survey It is evident from the large number of influ- eters.
in Germany, frequently asked coarser mixtures encing factors that there can be no standard for Normally, the energy consumption will rise
may cause a different ranking. the plant setting. linearly, while the pellet stability tends towards
The pelleting system has to be adapted to a final value the longer the die holes are.
Factors affecting pellet stability actual requirements by means of adjustment A considerable influence on pellet stability
T
he prosperity of industrial feed reduces microorganisms, the overall hygiene ments at same time, especially regarding the Feed ingredients influence pellet stability in and it has to cover a very wide spectrum. takes the press throughput.
compounding is based on the state is improved and storage periods may be fact that almost 80 percent of the total costs different ways. Manipulation is possible through die and For fixed die dimensions and a given
refining effect of mixed and extended - up to storage conditions, decay is are related to raw material input and a mere of While – depending on moisture content roller selection, rotary speed, gap width and number of die holes, the load of each hole
processed raw materials, especial- deferred. 20 percent is on hand with respect to technical and temperature – starch and protein may consequently pressure conditions, but also by increases with higher throughput: the power
ly since the introduction of the Benefits are not only given with respect to exercise of influence. cause more stable pellets, fat as a lubricant throughput and steam regulation, always tak- intake rises while the pellet-stability decreases.
pelleting process in the 1920s. transport and handling but also to livestock The production of firm and stable pellets reduces friction in the die holes and leads to ing due account of the motor load or current This can be explained by the minor compac-
management. Feed composition is guaranteed requires high pressure implying high energy weaker pellets. intake. tion of the thicker layer pressed into the holes
Compound feed complies with different even in small units, all components of the mix- consumption and/or reduced throughput. Increasing the fat contents leads to partial Longer die channels increase the prob- at a time [Reference 2].
quality attributes like hygienic and nutritional ture are incorporated homogeneously in the Fewer throughputs stand for extended reten- coating of the feed particles, which prevents the ability that binding will take place between
physiological aspects, technical characteristics, pellet, ensuring an even supply of ingredients tion time under pressure and thus produce penetration of the steam and thus the develop- the feed particles so that – supported by Double-stage pelleting
and environmental compatibility. Despite rais- and nutrients, selective feeding is impossible. better compaction. ment of binding agents – moisture bridges as enhanced frictional forces – the pellet durabil- Another important factor is the precom-
ing additional costs for equipment as well as Due to market conditions, the composition The specific energy demand rises anyway. well as the gelatinisation of starch [Reference 1]. ity is adequately improved. The same effect paction of the feedstuff before entering the die
for electrical and thermal energy consumption, or components may be changed without the But of course, pelleting is not just a matter
currently up to 70 percent of the compound risk of the feed being refused by the animals. of pressure and energy input.
feed produced in Europe and in the USA, are Palatability is also improved. The integrated The pelleting process can be divided in
pelleted. thermal process modifies starch and creates a three main procedures:
The requirements with respect to pellet certain taste and smell which, by the way, may - conditioning the pre-processed com-
quality, especially durability, differ according be covered by special additives in order make plete feed meal (complete except
to the animals to be fed, to the kind of live- the feedstuff distinctive. for sensitive micro components to We pride ourselves in implementing > Turnkey installations
stock breeding and in some cases to the be added on top or end of line) the latest technological
demand of the farmers too. - compacting and consolidat- improvements > Cleaning equipment
Pellets should be hard and resistant ing the mash into pellets
We strive for the highest quality > Milling equipment
to all demands placed on them from the - cooling the moist and hot pellets
& con dence in our products & > Transfer equipment
various stages in the production process to a storable and conveyable product services
to the feeding trough, be as dust-free Besides technological items material > Extraction Control
as possible and be of good appearance properties are of important impact. Next Our goal is complete customer > Packaging
in colour, texture and surface without to density, the particle size distribution is satisfaction in the production of
our our milling machines > Complementary machines
fractured areas which may cause abrasion. of special interest because it affects the
pelleting process significantly: from both
Advantages of pelleting theoretical and practical experience it is
Pelleting compound feed offers sev- well known that fine structured material
eral advantages compared to just ground, Figure 1 illustrates a typical but simplified flow almost allows trouble-free production
mixed mealy feedstuff. diagram of a feed production plant of firm pellets, but causes high energy
The hectolitre weight (tap density) of the consumption for milling.
bulk material is raised to some extent, so lower Digestibility is increased, thus the nutrient Coarsely grounding feed, at the recent
transportation and storage volume is required. utilisation is enhanced and there is less feed request of nutritionists, tends to produce less Konya Organize Sanayi Bölgesi 7 Sokak
Generally, pellets are free-flowing; arching in wastage. stable pellets, because bigger particles pre-
No: 3 Konya/TÜRKİYE
bins and silos is reduced. The efficiency of the pelleting process is determine breaking points within the pellets,
Emptying and dosing is quite easy with no measured by a large production throughput creating more cross sectional areas within the T: +90 332 239 1016 (pbx)
segregation arising within the product. at low power requirement and an output of pellet and thus more abrasion. F: +90 332 239 1348
Contamination risk from bins and hoppers pellets with low abrasion index, fulfilling high Depending on material’s properties (hard- E: unormak@unormak.com.tr
or even conveying equipment is of minor inter- quality aspects and resulting in almost low ness, brittleness or even flexibility) those par-
est because of the very small amount of resi- specific energy consumption (kWh/t). ticles are crushed between rollers and die
dues that arise when transporting stable pellets. These are conflicting objectives of high consuming more energy and causing probably
Heat treatment during the pelleting process demands and it is difficult to meet the require- more wear.
www.unormak.com.tr Realizing your future by your voice
Unormak.indd 1 24/11/2009 15:56
14 | July - august 2010 Grain &feed millinG technoloGy Grain &feed millinG technoloGy PREVIOUS PAGE NEXT PAGE July - august 2010 | 15

3. Energy consumption Feature Feature Energy consumption
hole – caused by double-stage pelleting, the establishing bonds between feed parti- steam. Adding as much steam as possible dur- Development trends include larger designs Heat recovery References
gap width between roller and die (automatic cles improving pellet stability. However ing pre-conditioning is thus desirable. for hammer mills, and the increased use of Additionally possibilities for heat recovery [1] Heidenreich, E. - Löwe, R. -
gap control) or the roller speed. The higher the increasing the amount of steam is limited Depending on absorbability and other fluids hammer mills with vertical rotors and roller from production processes for heating circuit Pelleting technology: looking to
speed (or the number of rollers), the smaller because of crossing admissible moisture within the mixture, and taking into account that mills with two or more assembly levels (roller water for social rooms or offices should be the future - International Milling
the material plug being pushed through the levels reducing the friction in front of and 0.6 percent of saturated steam will increase pairs with different gaps), either instead or reviewed. Directory 2000, pp. 55-60
bore, the better the compaction inside the within the die channels. process temperature by approximately ΔT = combined. Because of low enthalpy and possibly [2] Löwe, R. - Judging pellet stability
plug. 10 K (Figure 4), minimum content should be Both machines are preferable in terms of hygienic contamination direct use of thermal as part of pellet quality - Feed
Factors affecting energy approximately three percent (pelleting) to five energy use, but with roller mills material-specific energy from cooling or drying air for raw or Tech 9 (2005), pp. 15-19
consumption percent (expanding). processing restrictions need to be taken into feeder water is not recommended. A benefit [3] Birchmore, J. - Surfactant’s benefits to
Considering potential energy savings, specific However, steam input is limited due to account. from this energy recovery would rather be a feed manufacturers - Feed Magazine/
conditions of industrial compound feed produc- pressureless operation of the pre-conditioner reduction of odour emissions. Checking the Kraftfutter 3-4 (2010),pp. 17-21
tion need to be taken into account. Increasing by the maximum possible feed temperature possibilities of combined heat and power cycle [4] Feil, A - Is it possible to cut energy
customer focused production of small batches and moisture with respect to pelleting (lubricat- may be useful. costs for the production process?
as well as intensified use of hydrothermal- ing effect) and storage stability (moulding). The total energy requirement of a feedmill - IFF colloquium Braunschweig
mechanical treatment (in consequence of highly To ensure thermal energy is used efficiently, is decisively determined by plant layout, for- May 2005 International Research
demanded hygiene safety) ran up costs for loss minimisation and the maximum levels of mulation texture, type and technical state of Institute of Feed Technology
energy consumption (Reference 4). steam that can be added need to be consid- the equipment, plant capacity, load factor and [5] Löwe, R. - Vermahlungstechniken
To assess the energy efficiency of a proc- ered. Measures for saving thermal energy are, technological discipline among the staff. für Futtermittel - Tierernährung
ess, its specific electrical energy requirement for example, sufficient boiler pressure to allow In addition to the measures mentioned, für Tierärzte, TiHo Hannover
(kWh/t) should be related to effect-specific a drying phase by pressure reduction directly the prevention of energy losses (next to April 2007, Proceedings pp. 33-34;
Figure 2: compiles compacting energy consumption, for example with respect in front of the conditioner, accompanied by an steam accommodation pressure-air supply) Editor J. Kamphues and P. Wolf
affecting factors to the refinement process, refinement targets adequate number of steam traps, insulation of and the use of low-cost electricity rates
and capacity utilisation. all steam pipes, conditioners etc and of course basically re-present further optimisation
Figure 5: Influence of saturated steam
This would allow general conclusions stringent avoidance of leakages. potentials; in view of energy costs
addition on energy requirement, pellet More information:
regarding specific processability. durability and process temperatures developments, these should certainly be Website: www.iff-braunschweig.de
When comparing different sites within The grinding process taken into account.
one company, the balance sheets should be With respect to grinding processes, the
checked as to whether initial conditions are in specific energy requirement is determined by
fact comparable. An assessment always needs material properties, the required particle size
to consider not only energy consumption, but
also investments and amortisation, mainte-
reduction, the comminution equipment and
the process and plant layout.
Silo Construction & Engineering Quality grain storage
nance, wear and tear and the cost of spare Generally, particles should be only as fine as Modular square bins
parts [Reference 4]. We’re right up there
Figure 3: Breakdown of energy consumption Influences on energy consumption are
manifold: plant diagram, processing capacity
The addition of pelleting aids can bind,
and its utilisation are essential to realise aspired
processing aims.
more profits
for example fatty contents, by increasing the Handling hundreds of formulations and through Grain. Which is why we never
surface area; this may reduce pellet abrasion. producing batch sizes between 1.5 tonne
But the effect of auxiliary agents depends to a and 50 tonne is economically challenging. smart storage It’s your underestimate the importance
high extend on feed mixture recipes. Friction Besides structure of components and mixture business. of how it is handled.
reducing tensides or surface active agents may formulations technical condition of machinery If you need a partner with the
www.sce.be expertise, technology and
improve pelleting behaviour, too. and equipment as well as maintenance affect
manufacturing methods to
By facilitating the easier transfer of heat energy consumption.
ensure that your storage plant
(vapour) through the meal, which is con- Last but not least technological disci- Figure 4: Increase of temperature when is second-to-none in terms of
ditioned more intensively, surfactants may pline and education of the staff take effect conditioning compound feed by means of Now distributing quality and processes, then
reduce pellet press energy consumption. (Reference 4). saturated steam
Another effect is the possible reduction of Besides material, machine and process
Marot rotary look no further.
undesired moisture loss (shrink) which under parameters, the processing aims determine the necessary and as coarse as possible, since the cleaners and You can trust in Chief.
certain conditions may give support to raise the energy input: hygienisation efforts, reduction energy requirement rises exponentially with
production rate [Reference 3]. of antinutritive substances, decomposition of increasing fineness [Reference 5]. spares
SCE
Finer grinding of the compound-feed com- certain ingredients, pellet stability. Measures to discharge the mill-motor
ponents leads to larger specific surfaces and It is essential to understand that the higher load, such as the preliminary separating of
SCE is a partner with Beckingham Business Park
thus to more favourable conditions for the the targeted processing level, the higher the fines, closed-circuit processes or multi-level
the international Tolleshunt Major, Maldon
absorption of liquids and the effectiveness of energy input. Qualitative effects of refinement size reduction, can achieve energy savings of Essex CM9 8LZ, UK
the saturated steam and results in more firm processes are shown in Table 1. between five and 25 percent. Tel. +32- 51-72 31 28 feed & food industries • Tel +44 (0)1621 868944
pellets. In refinement processes, part of the electri- Frequency controlled drives allow selec- Fax +32- 51-72 53 50 consultancy & engineering firms • Fax +44 (0)1621 868955
Application of the saturated steam cal energy inputs can be provided by cost-effi- tive circumferential speed to realise roughly E-mail info@sce.be machine & plant designers • E-mail sales@chief.co.uk
creates more favourable conditions for cient thermal energy in the form of saturated aspired structures and particle size distributions. www.chief.co.uk
16 | July - august 2010 Grain &feed millinG technoloGy Grain &feed millinG technoloGy PREVIOUS PAGE NEXT PAGE July - august 2010 | 17

4. Content from the magazine is available to view free-of-charge, both as a full online magazine on our
website, and as an archive of individual features on the docstoc website.
LINKS
This digital Re-print is part of the July | August 2010 edition of Grain & Feed Milling Technology magazine.
Please click here to view our other publications on www.docstoc.com.
August 2010 • See the full issue
• Mycotoxin
testing:
ready for this year’s
harvest?
• Visit the GFMT website
In this issue:
• Added value • Technical design
• Contact the GFMT Team
by Flour Heat and equipment
Treatment - Key to improving
feed quality and
nutrition
• Factors affecting
pelleting
• Making Feed and energy
Pellets consumption
• Fusarium
mycotoxins
– What’s all the
• Subscribe to GFMT
fuss about?
A subscription magazine for the global flour & feed milling industries - first published in 1891
To purchase a paper copy of the magazine, or to subscribe to the paper edition please contact
our Circulation and Subscriptions Manager on the link adove.
INFORMATION FOR ADVERTISERS - CLICK HERE
Article reprints
All Grain & Feed Milling Tecchnology feature articles can be re-printed as a 4 or 8 page booklets (these have been used as point of sale materials, promotional materials for shows and exhibitions etc).
If you are interested in getting this article re-printed please contact the GFMT team for more information on - Tel: +44 1242 267707 - Email: jamest@gfmt.co.uk or visit www.gfmt.co.uk/reprints
www.gfmt.co.uk PREVIOUS PAGE