| 摘要 |
Method and device for separating a starting mixture into a higher-boiling and a lower-boiling fraction in a distillation apparatus operated in a continuous procedure, which apparatus contains at least one line for the feed of one or more starting mixtures, a take-off for the lower-boiling fraction, a take-off for the higher-boiling fraction, and a heating appliance, wherein the distillation apparatus contains at least two condensation stages each having a different temperature level, wherein the respective condensation stages which are upstream in the direction of flow of the vapours in each case have higher temperature levels than the respective downstream condensation stages, in each case internals having separating activity are connected intermediately of the condensation stages, partial condensations proceed at condensation stages, the sub-quantities which are not condensed in each case are fed to respectively downstream separating internals or condensation stages having respectively lower temperature levels and the condensed sub-quantities in each case are passed via separating internals in the direction of the take-off for the higher-boiling fraction, and essentially vaporous medium occurs at the condensation stage having the lowest temperature level and is partially condensed there, wherein the non-condensed-sub quantity of the medium is recirculated to the take-off for the lower-boiling fraction and the condensed sub-quantity is recirculated to a region of the distillation apparatus which is connected upstream of the condensation stage having the lowest temperature level, and the condensation stage having the lowest temperature level has a temperature of below -40°C. |
