To make good-quality pellets, the moisture content of the raw material plays an important role in the pelletizing process. Usually speaking, the moisture content ranges at 10-20% is the basic standard at producing qualified pellets. The optimum level is at appropriate 15%. Therefore, to control the moisture content, we need the help from dryer machine.
Rotary/Drum Dryers
The wet milled material is placed into the rotary dryer via screw auger. Hot air is generated at one end of the drum; a fan at the other end blow the hot air and material through the drum up to a cyclone separator. The drum rotates and thus produces a more effective drying process. Light dry particles come into the pipe, while heavy wet particles remain in the drum until dry.
Pipe Dryers
Place the wet material into the pipe dryer. Hot air is generated at one end of the pipe and a fan will sweep the hot air into the pipe ; the material then leaves the dryer via a cyclone separator.
The hot air in the dryer is generated by the oil or gas burners, but it is pricey and it is not environmental. It is suggested the lowest solution is burning the pellets as the heat source.