1. Moisture: 11%-13% for raw materials, 15%-17% after conditioning, generally 1% corresponds to 11°C;
2. Starch: raw starch has rough surface, large granulation resistance and poor adhesion; gelatinized starch has good adhesion and good particle quality.
3. The starch of barley and wheat is better than corn starch. Pellet yields are reduced if the grain has been cooked prior to conditioning (eg drying corn). Therefore, it is better not to choose drying when purchasing raw materials;
4. Protein: When the protein content in the formula is high, it is easier to granulate, and the quality of the granules is also better, because the plasticity and viscosity of the protein increase after being heated, so that the granulation yield is improved and the quality is good; when the protein content is too high, granulation The effect is reduced, because the ability to absorb steam is seriously reduced, and the tempering temperature is low. In addition, when non-protein nitrogen (such as urea, etc.) is high, the pelleting yield is reduced;
5. Fat: appropriate amount of fat, small friction resistance, small wear of ring die, low energy consumption, good quality of pellets, generally controlled within 3% before granulation; too high fat content, decreased pellet quality, soft and brittle pellets . When adding high-dose grease, it is advisable to add 30% of the full amount at the mixer, and spray 70% of the full amount after the granulator.
6. Crude fiber: Appropriate crude fiber content (3% to 5%) is beneficial to the bonding of pellets, reducing the pulverization rate of pellets and increasing the granulation output. However, when the crude fiber content exceeds 10%, due to the poor cohesion of the fiber itself, the binding force between the feed particles will be reduced, and the ability of the feed to absorb steam will also be affected. Severely increased.
7. Minerals: Inorganic feeds have almost no cohesion and poor pelleting performance, which affects the pelleting yield. When the inorganic content is high, a small amount of binder (such as molasses) is generally added to the material to improve the granulation performance and increase the output.
8. Binder: Appropriate binder can greatly improve the appearance quality, hardness, pulverization rate, water resistance, etc. of pellets, and can also improve the nutritional formula of feed. For example, adding 2~5% of bentonite to the feed can provide a variety of macro and trace elements for livestock and poultry, change the digestive function, and improve the nutrient utilization rate of the feed.
There are many kinds of binders, such as synthetic urea-formaldehyde resins, lignosulfonates, etc.; plant starches such as cassava, wheat, etc.; rare earth, clay types such as bentonite, attapulgite, etc. It should be selected reasonably according to the actual situation.