Design and construction of a liquid-liquid extractor utilizing ultrasonic energy

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1955
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Virginia Polytechnic Institute
Abstract

This investigation was conducted to provide laboratory scale equipment that will facilitate an accurate study of the affect of ultrasonic energy on mass transfer in two-phase multiple-component liquid systems.

A liquid-liquid extractor incorporating an ultrasonic generator and transducer was designed and constructed to the following specifications: (1) insonation frequency of 400 kilocycles per second, (2) insonation intensities equivalent to plate currents of 0 to 200 milliamperes, and (3) flow rate of solvent and feed through the reactor ranging approximately from one-half to 24 pounds per minute, in varying solvent-to-feed ratios.

A special glass reactor, or contactor, was constructed from a standard, 60° pyrexx glass funnel and fitted with an acoustical window of 0.001-inch sheet nickel. Photographic studies were made of the two-phase mixing taking place inside the reactor in both the presence and absence of ultrasonic insonation. An all metal reactor, of the same general design as the glass reactor, was constructed for use with the extractor when investigations were to be made that would involve high pressures or sudden liquid surges through the reactor.

An evaluation of the extractor was conducted employing the system moetons-water-1,1,2-trichloroethane. Stage efficiencies calculated for the individual tests, eleven in all, varied from 94.3 to 110.0 percent. An observed yellow color in the extract samples, probably due to dissolved impurities in the 1,1,2-trichloroethane, could have been responsible for the observation of refractive index readings that did not give true representation of the acetone concentration of the sample.

Cavitation was observed in the reactor which the test system was undergoing ultrasonic insonation. The gross stirring effects resulting from cavitation in the liquids caused a mixing of the two phases that was more intense than that taking place in the reactor without insonation.

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