The major reasons for ring die failure in biomass pellet production-1

Pellet machine is the key equipment in biomass pellet production, and the ring die is the heart of the working parts in pellet machine and also one of the most easy worn parts of pellet machine. The study on the failure reasons of the ring die has enormous influence on improving the conditions of the use of ring die, improving the product quality and yield, reducing energy consumption in biomass pellet production(pelleting energy consumption accounts for 30% ~ 30% of the total energy consumption of the entire workshop) and the production cost (cost of the loss of the ring die accounts for 25% ~ 30% of the repair cost of the whole production workshop) and so on.


 
In theory, a ring die and a pair of roller can produce 2000t and 500t of pellets respectively(regardless of high-grade ring die and roller). But in fact, enterprise of good management can only produce more than 1 000 tons and 250 tons; while general enterprise of poor management can only 500-600t and 80-100t, then the ring die and roller have to be changed. It shows that prolonging the service life of ring die will bring considerable benefits for the enterprise in biomass pellet production.
 
Working principle of ring die:
The rotating of ring die is driven by the motor through a reducer. The roller installed inside the ring die does not revolve, but rotates on its axis due to the friction with the rotating ring die (by pressing materials). After conditioning, materials would be sent into the crushing chamber and spread evenly between the roller by the feeder, then pressed by the roller clamp through the die holes of the ring die die with continuous extrusion and form columnar pellet and rotates with the ring die. Finally, the pellets formed would be cut into a certain length by the cutting knife fixed and installed on the outside of the ring die. The linear velocity of ring die and roller are the same at any contact point and all the pressure is used for pelleting.
 
In the normal working process of ring die, there is friction between the materials all the time. With the increase of the amount of material used in biomass pellet production, the ring die would wear gradually and ultimately lose its efficacy. Therefore, one of the indicators to measure the working performance of the ring die is the production. In the process of actual production, however, most of the ring dies have failed before reach the theoretic production capacity. Due to the higher cost of ring die, it will lead to a certain loss for the user. In the following content, we intend to analyze the failure causes of ring die, thus giving suggestions for the manufacturing and conditions of use of the ring die.
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