| 摘要 |
Method of operation for a continuous countercurrent extraction zone, to which a charge mixture stream and a solvent stream are continuously supplied and from which an extract stream and a raffinate stream are continuously withdrawn. In one embodiment, the method comprises establishing a recycle stream consisting of a portion of the light phase stream withdrawn from the column, combining the recycle stream with the charge mixture stream, and controlling the streams flowing to and from the column. The combined feed stream to the extraction zone is controlled at a constant flow rate and recycle flow has preference over charge mixture flow, thereby causing charge stream flow to vary inversely with recycle flow. An important feature of the invention resides in adjustment of composition of this total combined feed stream to the extraction zone in order to deal with fluctuations in other parameters. The effects of fluctuations in flow rates and compositions of streams entering and leaving an extraction zone are mitigated, resulting in increased efficiency.
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