Process for subsequent condensation of polycondensates, in particular of polyamide 6.6

摘要

PCT No. PCT/CH95/00307 Sec. 371 Date Aug. 26, 1997 Sec. 102(e) Date Aug. 26, 1997 PCT Filed Dec. 27, 1995 PCT Pub. No. WO97/24389 PCT Pub. Date Jul. 10, 1997The process for single-stage postcondensation of a polycondensate in a fluidized bed reactor (1) includes feeding the polycondensate through the fluidized bed reactor (1); circulating a main stream of nitrogen carrier gas through the fluidized bed reactor; withdrawing a fractional stream at a temperature of from 20 DEG to 230 DEG C. from the main stream of the nitrogen carrier gas; passing the fractional stream through a water-filled gas scrubber column (15) so as to form a conditioned stream of the nitrogen carrier gas with a predetermined dew point between 10 DEG to 80 DEG C.; and returning the conditioned stream to the main stream. In preferred embodiments the polycondensate is allowed to cool during a cool-down stage at an end of the postcondensation and the withdrawal of the fractional stream from the main stream is halted, but the circulating of the main stream through the fluidized bed reactor is continued during the cool-down stage.