CONTINUOUS METHOD FOR MULTI-STAGED DRYING AND SUBSEQUENT CONDENSATION OF A POLYAMIDE GRANULATE
A continuous process for the multistage drying and postcondensation of polyamide pellets in the solid phase comprises 1) carrying out the predrying process in a continuous drying apparatus which is operated in countercurrent mode or in crossflow mode with inert gas or steam, or with a mixture of ine...
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Sprache: | eng ; fre ; ger |
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Zusammenfassung: | A continuous process for the multistage drying and postcondensation of polyamide pellets in the solid phase comprises 1) carrying out the predrying process in a continuous drying apparatus which is operated in countercurrent mode or in crossflow mode with inert gas or steam, or with a mixture of inert gas and steam, using a pellet temperature in the range from 70 to 200° C., and 2) Carrying out the subsequent continuous postcondensation process in a separate vertical duct with moving bed at a pellet temperature in the range from 120 to 210° C., where the duct is operated in countercurrent mode with inert gas or steam, or with a mixture of inert gas and steam, 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 below the surface of the pellets. |
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