In the production process of compound feed, the safe and normal production of the pellet mill is very important, because the preparation of pellets is completely completed by the pellet mill. However, in actual production, due to various reasons, it is easy to form a thick and hard material "crust" between the ring die and the pressure roller, and the pressure roller cannot squeeze the material out of the die hole, which makes the ring die of the granulator jam. Dead or slippery, causing the common phenomenon of granulator blockage.

Through the on-site analysis of multiple equipment and multiple materials, in fact, the reasons for the blockage are as follows:

1. The mold roll gap is inappropriate
The gap between the mold rolls is too large, causing the material layer between the mold rolls to be too thick and unevenly distributed, and the pressure roll is easy to slip due to uneven force. Once the squeezing force of the die roller on the material is less than the resistance of the inner wall of the die hole to the material, the material cannot be squeezed out and the machine will be blocked. In order to reduce machine blockage, attention should be paid to adjusting the gap between the mold rolls during production. When adjusting, the pressure roll and the ring mold should form a state of "seeming but not relying, like turning and not turning". According to observations, the gap is normal. It is 3-5mm. Among them, the experience of the granulator and the adjustment feel are very important.

2. The influence of steam
The most ideal production condition elements in the pellet feed production process are: the raw material moisture is appropriate, the steam quality is good, and there is sufficient conditioning time. The correct use of dry saturated steam for granulation can effectively improve the output of the granulator and the quality of the pellets. To ensure good pellet quality and high output, in addition to the normal operation of the various transmission parts of the pellet mill, the quality of the dry saturated steam entering the pellet mill conditioner should also be ensured. Applicable saturated steam has a softening and lubricating effect in the granulation process, which can increase productivity, reduce frictional heat energy, and extend the service life of ring die; it can reduce power consumption, promote starch gelation, and fibrous fiber bonding; it can increase particles The molding rate is reduced, the powder material is reduced, and the material appearance is smooth and tidy, thereby improving the competitiveness of the product.
Poor steam quality makes the material too high when it exits the conditioner, and it is easy to cause blockage of the die hole when the granule cavity is formed, and the pressure roller slips, resulting in a blockage. The specific manifestations are as follows: ① Insufficient steam pressure and high water content make the material absorb too much water. At the same time, when the pressure is low, the temperature when the material is tempered is also low, starch cannot be gelatinized well, and the granulation effect is poor; ② Steam The pressure is unstable, high and low, and the condition of material conditioning is unstable, which leads to large fluctuations in the current of the granulator, uneven material thirst, and it is easy to cause the machine to block in the normal production process.
The granulator must pay attention to various factors such as steam pressure and the feed volume of the conditioner at any time to avoid excessively high moisture content in the material caused by the steam pressure and water content. At the same time, in order to reduce the number of blockages caused by steam quality, the boiler room should provide high-quality and stable dry saturated steam. During the production process, the granulator should always pay attention to the moisture content of the quenched and tempered material. A simple method can be used to determine it. The specific method is: grab a handful of the material out of the conditioner and hold it into a mass, and let it go.

3. The influence of quenching and tempering effect
To make pellet feed meet the competitive demands of the market, it is necessary to ensure its high quality. The conditioning effect of the material before granulation is very important, because it directly affects the output of the granulator and the quality of the pellet, especially the water stability of the special aquatic product is an important indicator. If the material cannot be fully tempered and matured before granulation, its water stability index will be difficult to guarantee. The so-called conditioning is the pretreatment of the powdered material before granulation, which is the process of fully stirring and absorbing the powder to be granulated and an appropriate amount of steam in the conditioner. Select the conditioning equipment that meets the technical requirements, so that the material can be fully stirred and mixed with steam in the conditioner to achieve the function of softening the material and gelatinized starch, which is conducive to the compaction of the powder and the production of qualified products. The conditioner needs to have a long time of heat preservation, heating and humidification, and the number of layers can be combined and installed as needed to ensure that the material fully meets the requirements of the conditioning, improve the surface and internal quality of the pellets, and improve their water resistance in water. The most advanced method at this stage is the use of modulator + quality assurance device + modulator, which can achieve the most ideal quenching and tempering effect.
Through on-site debugging, the number of blockages of the pellet machine can be reduced, which can be solved by adjusting the steam. Since the boiler equipment has been finalized, the steam provided has been determined. Pay attention to the treatment method of water vapor in the steam pipeline, try to remove the condensed water in the steam pipeline, and the steam pressure at the front end of the conditioner must be very stable.

The above is the personal experience gained in the long-term production process and technical service work. Due to various factors, it is inevitable that there are certain limitations. I hope to exchange and learn with everyone.