METHOD OF CONTROLLING EXTRACTION OF CAPROLACTAM Russian patent published in 2012 - IPC C07D201/16 B01D11/04 G05D27/00 

FIELD: chemistry.

SUBSTANCE: disclosed is a method of extracting and purifying caprolactam from a mixture with water and impurities with trichloroethylene from lactam oil with subsequent re-extraction of caprolactam with water. Extraction is controlled in two stages connected to each other while feeding lactam oil, trichloroethylene and condensate to extractors of the first stage and re-extraction of caprolactam from trichloroethylene with water at the second stage with removal of caprolactam to the next stages, further comprising a pump for feeding lactam oil with a flow sensor and a valve, a pump for feeding regenerated trichloroethylene with a flow sensor and a valve, a pump for feeding circulation trichloroethylene with a flow sensor and a valve; a device for feeding a weak trichloroethylene solution into the middle part of the oscillating extractor of the first stage with a temperature sensor whose first output is connected to a pipe for feeding the raffinate into the rotory extractor of the first stage with a temperature sensor, and the second output is connected to the phase separation device of the oscillating extractor of the first stage, connected to the separator of the first stage, the first output of which is connected to the top part of the oscillating and rotary extractor of the second stage with temperature sensors, and the second output is connected to the middle part of the rotary extractor of the second stage, wherein regenerated trichloroethylene is fed into the top part of the rotary extractor of the second stage; a pump for feeding condensate with a flow sensor and a valve to the output of the caprolactam solution in trichloroethylene from the oscillating extractor of the first stage, the output of the rotary extractor of the first stage and through a pipe with a sensor and a valve to the middle part of the oscillating extractor of the second stage, into the bottom part of which condensate is fed from the collector with a sensor and a valve; wherein the output of the rotary extractor of the first stage is connected to the phase separation device of the rotary extractor of the first stage, connected to the separator of the second stage, the first output of which is connected to the top part of the oscillating extractor of the second stage, and the second output is connected to the collector; outputs of the bottom part of the oscillating and rotary extractors of the second stage are connected to the phase separation device of oscillating and rotary extractor, connected to the collector for distilling off trichloroethylene from water; the output of the top part of the oscillating extractor of the second stage is connected through the collector to the pump for distilling of trichloroethylene; wherein a pump with a flow sensor and a valve feed into the bottom part of the oscillating extractor a temperature sensor for distilling off ammonium sulphate, ammonium sulphate solution from the regrouping and neutralisation stage, wherein from the bottom part the stream is fed through the device for feeding weak trichloroethylene solution into the middle part of the oscillating extractor of the first stage, and ammonium sulphate solution from the top part of the oscillating extractor is fed into the ammonium sulphate collector, wherein the flow rate of lactam oil to extractors of the first stage is set and the flow rate of the regenerated and circulation trichloroethylene and condensate into extractors of the first and second stages is respectively corrected by adjusting the valve; flow rate of ammonium sulphate from the regrouping and neutralisation stage is set and corrected depending the flow rate to the extractor.

EFFECT: high efficiency, improved quality and reduced loss of caprolactam is achieved by introducing a distribution device which enables to feed streams to different points of extractors.

1 cl, 1 ex, 1 tbl, 1 dwg