In the process of pellet feed processing, the phenomenon of high pulverization rate not only causes damage to feed quality, but also leads to an increase in processing costs, and causes certain troubles to feed storage and transportation. Therefore, the control of the pulverization rate is crucial. In order to control the chalking rate, it is first necessary to accurately measure the chalking rate. Although most feed mills conduct sampling measurement after the finished product is packed or stacked, although the test results intuitively reflect the pulverization rate of the feed, it cannot reflect the factors that fluctuate the pulverization rate in each process.
Therefore, in order to monitor each process more effectively and achieve the goal of prevention first, prevention and control at the same time, we recommend that manufacturers need to monitor each process. In addition, in order to ensure the quality and stability of the feed, we also recommend that the manufacturer needs to determine the pulverization rate of the feed before it is transported to the farmer and fed, which is more representative of the final pulverization rate quality result of the feed.
The following is an analysis of each process link:
Recipe:Generally speaking, crude protein, crude fat content is lower feed, its granulation processing is easy, on the contrary, crude protein, crude fat content is higher to make it difficult to form after granulation, loose particles, high pulverization rate. Considering the feed quality, the formula is the premise, and the difficulty of granulation should be considered as much as possible in the case of meeting the nutrient ratio. In order to ensure the comprehensive quality.
Crushing process:The size of the feed crushing particle size directly affects the quality of granulation, the smaller the particles, the larger the surface area of the material per unit weight, the better the cohesiveness during granulation, the higher the granulation quality, and vice versa, it affects the granulation quality, but the crushing granularity is too small, resulting in the increase in the cost of the crushing process, and the destruction of some nutrients.
Suggestion: Powder size of livestock and poultry feed before granulation: more than 16 mesh. Powder particle size before pelletizing of aquatic feed: more than 40 mesh.
Granulation process:
First of all, quenching and tempering is the key, if the quenching and tempering is not sufficient, it will directly affect the granulation quality; The factors mainly include quenching and tempering time, steam pressure, steam temperature, etc., and the main indicators of the results are reflected in the quenching and tempering moisture and quenching temperature. The quenching and tempering water content is too low or too high, and the conditioning temperature is too low or too high to have a great impact on the granulation quality, especially if it is too low, the feed pellets will not be compact, and the particle breakage rate and pulverization rate will increase, which will not only affect the quality of the pellets, but also increase the processing cost and lose some nutrients due to the reverse replication of the grain after screening.
Suggestion: control the quenching and tempering moisture at 15-17%. Temperature: 70-90 (the incoming steam should be depressurized to 220-500kpa, and the incoming steam temperature should be controlled at about 115-125).
Factors for pellet quality in a granulator include:
According to different varieties, different specifications of ring dies are selected, and some varieties with high protein and fat content require the selection of thickened ring dies.
During operation, the flow rate of the material between the pressure roller and the ring die, and the regulation of the temperature of the material out of the machine have different degrees of influence on the granulation quality, and the selection of particle size and length is also worth considering.
It is recommended to control the discharge temperature at about 76-92 (the discharge temperature is too low, especially the feed is not ripened enough, and the hardness of the particles is reduced).
4. ColdBut the process:In this process, if the material is cooled unevenly or the cooling time is too fast, it will cause the particles to burst the waist, resulting in irregular and easy fracture of the feed surface, thereby increasing the pulverization rate.
5. Vibrating classifier:
If the grading sieve layer is too thick or unevenly distributed, it is easy to cause incomplete screening, so that the powder in the finished product increases.
The cooler is discharged too fast, which can easily cause the grading screen layer to be too thick, especially for particle size 25mm.
6. Finished product packaging process:
Since the finished product warehouse extends from the top floor of the plant all the way to the bottom floor, a significant drop has been formed, which requires us to store at least 1 3 quantities in the continuous production process before we can start the packaging process. The aim of this arrangement is to prevent the feed from falling from a height and breaking it, thereby reducing the powder content in the finished product. Especially for those materials with a high pulverization rate, we should follow this principle.
To sum up, in the process of pellet feed production, the pulverization rate is affected by multiple factors, and the ways to control the pulverization rate are not the same due to the differences in formula, equipment and processing technology of various feed manufacturers. Usually, manufacturers will work process operation control and strive to do a good job in process control to avoid the increase in pulverization rate caused by improper operation. However, for some varieties, due to the limitation of nutrient requirements or processing equipment technology, process control alone cannot effectively reduce the pulverization rate, so it is necessary to consider adding binders to assist in granulation. In this way, the high investment caused by large-scale equipment modification can be avoided. Especially for aquafeeds, the addition of binders can significantly improve the quality of feed pellets and the retention time in water due to their special nutritional requirements, physiological properties and feeding characteristics. By using binders wisely, we are able to meet the needs of aquaculture, while reducing production costs and improving economic efficiency.