Patent ID: 6413429
Filing Date: 2002-07-02
Classification: B01D,Y10S

Abstract:
A process for extracting a component dissolved in a first liquid to be extracted by means of liquid-liquid extraction using an extraction liquid which is immiscible or only partially miscible with the liquid to be extracted in which process the extraction liquid is dispersed in the liquid in a dispersion apparatus and then coalesced in a coalescer, after which the extraction liquid, the specific weight of which differs by at least 5% from the specific weight of the liquid to be extracted in which the component to be extracted is to be found, is separated from the first liquid by gravity in a phase separator, characterised in that in order to obtain an efficiency per extraction stage of at least 0.9 at an average residence time of at most 15 seconds in the dispersion apparatus and of at most 300 seconds in the phase separator, at a linear velocity in the coalescer related to its cross-section of at least 30 m/hour:a. the dispersion apparatus used is a centrifugal pump which will give droplets having an average diameter of 5 to 500 &mgr;m, b. the coalescer used is a packed bed of 5-100 cm high comprised of dimensionally stable particles wettable by the extraction liquid having an average particle size of 0.05 to 2 mm, and c. the coagulated phase in the phase separator is separated at a linear velocity related to the cross-section of the phase separator of 0.1 to 0.7 times the linear velocity related to the cross section of the coalescer.