Pellet Treatment Unit

A method for reducing volatiles in polyethylene pellets that comprises the steps of:

• a) retrieving the pellets from the extruder (1) and pushing them through a cooling pipe (3) with a stream of cooling water and with a residence time sufficient to reach the desired temperature;
• b) separating the pellets from the water in a dryer (4), returning the water to the cooling system via a cooling device (5) and pushing the cooled pellets through a pipe (9) into the heating silo (10);
• c) keeping the pellets for a period of time of from 5 to 50 hours in the heating silo under a stream of hot gas (11) entering near the lower end of the heating silo and escaping through the upper open surface;
• d) continuously retrieving pellets through the bottom part of the heating silo via a valve (24) that allows control of the exiting flow of material in order to keep the heating silo constantly full;
• e) feeding the pellets to the cooling device (25);
• f) keeping the cooling device at room temperature to bring the pellets' temperature down to the desired level of from 60 to 70° C.;
• g) sending the cooled pellets to the homogenisation silos.