METHOD FOR SEPARATING MATERIALS BY MEANS OF AN EXTRACTIVE DISTILLATION PROCESS

摘要

A method for separating a mixture of materials A and B by extractive distillation, using an extraction medium having a higher affinity to B than to A, wherein a feed stream comprising A and B is conducted towards the extraction medium in a column, wherein an overhead fraction comprising A and also a liquid fraction comprising B and extraction medium are obtained, the liquid fraction is collected on a collecting tray and heated and partially evaporated in a first indirect heat exchanger, the resultant vapor is released into the column and a non-evaporated proportion of the liquid fraction is collected as sump fraction in the sump of the column, the sump fraction is successively heated in a second indirect heat exchanger and a third indirect heat exchanger and in part evaporated, wherein the resultant vapor is at least in part released into the column, the sump fraction is separated in a stripper into a fraction comprising B and an extraction medium fraction, the extraction medium fraction is used as heating medium for the second heat exchanger, wherein a partially cooled extraction medium fraction is obtained, and an external heating medium is used for the third heat exchanger, and the partially cooled extraction medium fraction is used as heating medium for the first heat exchanger.