AN EXTRACTIVE DISTILLATION APPARATUS

摘要

A process and apparatus are provided controlling the heat input of an extractive distillation column. The bottom of the column is heated with a major stream of thermal energy which is either slowly varying in time or controlled by the amount of starting material mixture and with a minor stream of thermal energy which is controlled by sensing the thermodynamic state in the upper half of the column during the process. The major stream can provide about 90 percent and the minor stream about 10 percent of the heat fed to the column. The minor stream can be controlled by the temperature at one point in the upper half of the column, by the temperature difference at two points in the upper half of the column or by gas chromatographic analysis of the extract material concentration near the top of the column. The process allows one to keep a low concentration of the extract material in the raffinate.