Patent ID: 8877107
Filing Date: 2014-11-04
Classification: B01J,B29B,C08G,F26B

Abstract:
1. A method for direct increase in the molecular weight using the residual heat during the production of a non-adhering polyester granulate, comprising steps in which a) a polyester raw material as melt is pressed through a nozzle, granulated in a cooling water flow and, after passing through a cooling water stretch, is separated from the cooling water flow, and b) a bed of the granulate obtained in step a) is subjected, directly following step a), to a thermal drying and post-treatment by supplying the granulate bed with a gas flow of a gas or gas mixture, the thermal drying and post treatment being conducted in a silo wherein the gas flow of a gas or gas mixture is conducted from bottom to top through the granulate bed and the dew point of the gas or gas mixture before being supplied is ≦ wherein during step b), the dwell time of the granulate is between one and thirty hours and neither the granulate used nor the supplied gas or gas mixture of the gas flow is heated by external energy input, and the gas flow is conducted in counterflow to the conduction direction of the granulate in the silo, and the average temperature of the bed of the granulate before entry in step b) is adjusted to more than 170° C.