Patent ID: 8703879

Claim:
A continuous process for the multistage predrying and post condensation of polyamide pellets in the solid phase, which comprises 1) carrying out a predrying process in a continuous drying apparatus which is operated in countercurrent mode with inert gas and by maintaining the temperature of the polyamide pellets in the range from 140 to 180° C., and 2) carrying out a subsequent continuous postcondensation process in a second apparatus comprising a vertical duct with moving bed at a temperature of the polyamide pellets in the range from 120 to 210° C., where the duct is operated in countercurrent mode with an inert gas, wherein the inert gas is introduced at least two sites along the duct, and from 15 to 90% of the inert gas is introduced at the base of the vertical duct and from 10 to 85% of the inert gas is introduced in the upper half of the length of the vertical duct below the surface of the pellets.