METHOD FOR AFTER-TREATMENT OF PRODUCT AT TOWER BOTTOM IN EXTRACTIVE DISTILLATION PROCESS

摘要

PURPOSE: To obtain with high thermal efficiency pure aromatic compounds by passing sump product obtained from an extractive distillation column through two side reboilers connected in series before introduction to stripping column to cool it by indirect heat-exchange with product stream generated form the step in the reboiler. CONSTITUTION: A sump product of an extractive distillation column 2 is passed through two side reboilers 9, 14 before introduction to a stripping column 15 and is cooled to a temperature of 105 to 120 deg.C by indirect heat exchange with the product flow generated from the steps in the reboilers, whereby heat released by cooling the sump product is used for heating a reflux flowing from the bottom part to upper part of the stripping column 15. As a result, a pure aromatic compound can be obtained with high thermal efficiency.