2012年4月18日星期三

Cooling Pellets

The materials will release energy in form of heat when they are compacted or compressed to generate pellets. This process is called adiabatic process. Hot pellets can cause serious injuries and damage to mill operator and the pellet mill packaging bags respectively because this heat can soar as high as 80 degrees centigrade in pellet generation process. Way to cool down pellets to a temperature which is not dangerous to the handlers and also not damaging to the pellet packaging is obbligato. For this reason, there is a need of a pellet mill cooler.



Due to the different output of the mills, the considerations of the coolers are also varied. In case the mill is an industrial class pellet milling, the amount of time the pellet should remain in the cooler has to be very short else it is bound to cause congestion. It is necessary to weigh against the temperature the pellet will have as it exits the pellet mill cooler. Therefore, the output of the coolers decide the difference in the change of temperature between entering the cooler and exiting the cooler.



Hot pellets are easily broken down into fine powder they were made from besides harm that the temperature can cause the packaging. This is due to the presence of moisture which is around 15% after compacting process ends. Both the needless heat and water moisture will be eliminated in the cooling process. Thus, reducing the moisture levels by 4% to 5%. Eliminating redundant moisture help prevent fungal colonies.



The most popular type of pellet cooler is the counter flow cooler. The cooler will blow cool air to the hot pellets in the opposite direction to bring down the temperature. Because it carries hot moist air deeper into the cooler away from the pellet's exit, the cooling process is efficient, avoiding the pellets coming into contact with the heated moist air is a must do. This cooler can cool the hot pellet evenly. One can combine the cooler with his pellet mill plant. Using this type of cooler may cause factorization and abrasion to pellet.



Cooling conveyor which allows the pellets to dissipate the heat it has acquired while meandering towards the packaging section is also a way to cool the pellets. This doesn't have maintenance problem but instead the needless water content can't be eliminated.



Another revolutionary method of cooling pellets is by use of heat exchangers which draw the temperature from the pellets without risking them falling apart. As the pellets pass through the bank of heat exchangers, their temperature and along with it the moisture is extracted. This cooler has got many the advantages but it may blow pellets to broken. And it can't extract water content well.

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