Principles of the feed processing Ozren Zimonja, PhD Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway, E-mail: ozren.zimonja@umb.no
History of the Feed Manufacturing Prehistoric times when cereals were ground before fed to animals. Only few developments before industrial revolution - late 19 th century Quickly dominated by engineers and machines Further challenge: bridge the knowledge between physics/technology, nutrition/animals and food chem. Grinding of seeds in the stone-age
Why process the feeds One of the major goals of feed production is to combine different feed ingredients formulated to meet specific nutrient requirements (complete or partial) - compound feed Feed ingredients exist in varying particle size and form, and thus purposes of feed processing is a modification of the structure of the feed, thermal treatments of the feed and subsequent shaping of the feed
Why process the feeds Increase in nutritional value of the nutrients e.g. - in swine improve digestion of the starch by gelatinisation Increase in feed intake e.g. - broiler chickens Better hygienic quality e.g. salmonella Elimination of the unwanted components e.g. trypsin inhibitors in soy
Silos Manufacturer:Norsk fôrteknologi AS Capacity:3 x 16000 for grain (capacity 16 m3 each ) 1 x 16000 l. grain or meal (capacity 16m3) Designed mainly for the bulk storage of grain. The fourth silo also has a screw agitator that allows it to be used for meal and pre mixes as well as grain. The grain is transported into the building by means of conveyors and elevators fitted with dust filters supplied by Jesma Co. (Sprout Matador)
Sifter Manufacturer:Jesma Co (Sprout Matador), Denmark Capacity:5 ton/hour A sifter, or screen like device placed before a hammer mill, has the purpose of separating particle sizes of the meal or grain that is feeding it with very little influence from the density of the particle. A sifter is placed before a hammer mill in order to avoid grinding small particles that are already small enough in relation to the particles that will go through the hammer mill.
Grinding section Hammer Mill Roller Mill
Hammer mill Hammer mill accomplish size reduction by impacting a slow moving target, such as a cereal grain, with a rapidly moving hammer. Sizing is a function of hammer-tip speed; hammer design and placement; screen design and hole size; and whether or not air assist is used
Roller mill Roller mill accomplish particle size reduction by pressing material between rolls. Sizing will vary according to the nature of material, distance between rolls
Manufacturer:Abel Company, Wisconsin, USA Capacity:4 ton/hour Capacity:22 Batching Bins as follows: 4 x 1200 lt. 2 x Big Bag (500 kg each) 8 x 600 lt. 8 x 120 lt. Dosing System 14 of the 22 silos can be filled automatically from the outside intake, mills or big bag intake. The 8 x 120 lt. silos are filled by hand and are specifically for micro ingredients giving a batching accuracy to within less than 50g in a 200kg. batch. The dosing system operates automatically from the main computer system. A formula is sent to this main frame system by a nutritionist and the computer tells, via electronic signal, what to take out of each silo.
Weighing
Mixing
Mixer Conditioner Manufacturerof the basic mixer:tatham of England under license from Forberg, Norway Model:Twin Shaft Capacity:400 lt. Motor Kw.:4 kw The mixer conditioner is a brand new concept in feed milling and it is the creation of FôrTek personnel in collaboration with Dinnissen b.v. of Holland. A regular paddle mixer was converted into a mixer where hot air, steam, electrical heaters and hot water, can all be combined for heating meal up to 90 degrees for unlimited time.
Pelleting Pelleting process has been introduced into feed industry in begining of 20 th century. Pelleting can be defined as the agglomeration (process of molding into mass) of small particles into larger particles by means of mechanical process in combination with moisture, heat and pressure! A majority of the 600 million tons of concentrates produced annually are pelleted
Reasons for pelleting Pellets have better flow properties and discharging behaviour from silos than the meal Less dust problems with pellets than meal Higher bulk density of pellets than meal The composition of the pellets remains fixed, no segregation of e.g additives
Twin Pass Conditioner Manufacturer:Muench, Germany Model:Twin Pass Capacity:5000Kgs./hr Dimensions:2 x 2m x 40cm. The twin pass conditioner is used to give very thorough heating of the meal. Steam can be added to the top or bottom conditioner or both as required. Pellet Press Manufacturer:Muench, Germany Model: Capacity:Min. 300kgs./hr Max. 5000Kgs./hr Motor Kw.:2 x 17 kw
Conditioning process Conditioning temp: max 90ºC 2-6 % of added moisture Time: ~ 20-40 sec
Pellet die Friction-Temperature Pressure Chemical changes of the components new bonds under moisture, temperature, pressure + time
Expander More severe process Expander barrel Pressure issue
Expansion Pelleting Pressure: up to 50 bars Temperature: 130ºC Posibility - water in the expander barrel Pelleting or crumbling
Expander processing feed is heated in the conditioner to 70-90 C 18% (up to 24-28%) water the pressure is allowed to rise to a level of 15-50 bars temperature increase up to 130 C feed mash leaves the expander, a sudden drop in pressure occurs, where added water evaporates spontaneously (effect is called 'flashing' )
Definition of extrusion Extrusion is defined as The process by which moistened, expansible, starch and/or proteinous materials are plasticized and cooked in a tube by a combination of moisture, pressure, temperature and mechanical shear. Extrusion of feed is a combination of heat; shear and pressure build up in the presence of water.
Prebin I Extrusion Basics Thoroughly mixed before entering the pre-bin The feed here (FôrTek are volumetric, not gravimetric The feeder needs to be calibrated before each new material (hazzle) The bin should be equal filled all time to ensure constant pressure on material ( constant feeding) Wet material has quite another density than Prebin dry material (you need to calibrate) II (Pre)conditioner coater extruder dryer cooler mixer
Extrusion Line surge bin ingredient feeder agitator water addition volumetric feeder to vacuum pump conditioner steam to conditioner steam to conditioner venting direct steam additon slurry pump 72 kw at ca. 450 rpm to suction pneumatic
Pre-conditioner (NOT a mixer) Raw Material Steam and liquids High rpm Mixing unit Retention unit Conditioned Material Low rpm
The Screw Elements 1 st 2 nd 3 rd 4 th 5 th 4 6 2: Feeding 4: Pressure generation, heat transfer high fill 6: Reverse conveying elements 10: Forward Polygon: Kneading effect. High shear, (Can be both forward and backward, i.e. Left and right handed) (interrupted melt flow)
Advantages Extrusion/Expansion increased temperatures increased fat addition (90 C to 160 C) (30% or more) increased molasses addition (up to 15%) gelatinization of starch (70% to 95%) pasteurized/sterilised feed (90 C to 160 C) improved pellet durability (up to 20%) increased production capacity (up to 50%) lower dust quantities a more flexible process
Disadvantages Bigger energy consumption compared with other processes. More expensive than pelleting with regular conditioning.
Manufacturer:Miltenz, New Zealand Model: Capacity:2 ton/hour Motor:None Uses ambient air Coolers are used for reducing the temparature of the finished product. Depending on which process is used the product when entering the cooler will be between 80 degrees C. and 150 degrees C. If the product is packed at this temp. it will mould so cooling down to ambient temp. is required. FôrTek has two coolers in the line, one after the pellet press and one after vacuum coating Cooler
Drier Manufacturer:Miltenz, New Zealand Model:VD 010 Capacity:1500 Kgs/Hr Burner:Rutiomatic 50 RM v.2 Counter flow gas heated drier. This equipment is used for the extruder product that may contain as much as 30% moisture at the discharge point and that must be reduced to under 8% before going to the vacuum coater for high liquid addition. Belt driers are more commonly used for this process.
Desirable properties of feed Durable pellet that does not break during transportation or in the feeders Pellet that produce minimal amount of dust Reduced loss
Quality of the pellets
Holmen Durability Tester
Ingredient factors Cereals - major component of concentrates Starch - dominant feed component Chemical changes of the starch and proteins due to thermal and mechanical process of pelleting
Starch modification Graph provided by Bühler AG
Starch
Starch gelatinisation
Proteins: denaturation
Processing factors: gelatinisation, denaturation Starch gelatinisation - temperature: 50 70 C - moisture: 30% (Lund, 1984; Jacobs and Delcour, 1998) gel. temperature rises to 125 C Protein denaturation - highly dependant of the source of the proteins and moisture content: temperature: usually below 100 C e.g. wheat gluten - at room temperature soy proteins over 150 C at 29% moisture
Processing factors: pelleting and extrusion Pelleting: - moisture: max. 18% - temperature: 90 C (max about 95 C) - retention time: seconds - shear: low Extrusion: - moisture: about 35% - temperature: 140 C ++ - retention time: seconds - shear: high
Effects of feed processes on gelatinisation 100 80 89.9 91.2 % 60 40 20 16.1 29.1 12.4 20.1 0 SP EXT SP EXT SP EXP-P Wheat Oats Wheat-Barley Zimonja et al. (2007; 2008ab)
Effects of starch on physical pellet quality % 50 45 40 35 30 25 20 15 10 5 0 A B C D E CP CP SP SP SP Non Starch Starch Non starch Starch Gel Starch Zimonja and Svihus (2008)
Processing parameters: extrusion Graph provided by Bühler AG
Thank you for your attention