| 摘要 |
Process for removing distillate from a low pressure distillation column, in partic. an automatic TBP type column, extending between a base or boiler heated to a predetermined temp. into which a load is introduced at the start of the distillation, and a head or condenser where a cooling fluid circulates cooled to a predetermined temp. A controlled predetermined portion of the distillate is removed from the outlet of the condenser and transferred to a receiver. The process involves repeatedly extracting and recovering different fractions of the distillate between two vapour temp. limits or for given fractions by mass or vol. of the load. The extractors are connected to two watertight extraction chambers designed to receive one dose. Each chamber can be connected to or isolated from the extractors and/or the pressure in the column. At the end of each extraction or when the first chamber is full, the extractors are switched to the second chamber without interruption. The first chamber is then isolated from the column before bringing it to ambient pressure, removing the dose and returning it to the column pressure. This is done without disturbing the pressure in the column. Device for carrying out the above process, with the following parts; an extraction tube (7) with a valve (8) to allow the extracted proportion of distillate to be controlled. The tube divides into two branches (7A,7B) at its end, two extraction chambers (A,B), a circuit (D) for putting the extraction chambers under vacuum, a circuit (E) for re-pressurising the extraction chambers, connected to air or nitrogen.
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