Measurement of liquid hold-up of the dispersed phase by an ultrasonic method

A new method has been proposed of the continuous detection of the volume hold-up of the dispersed phase in a liquid-liquid system. The method utilizes different velocities of sound in the organic and the water phase and has been tested on four liquid systems typical for liquid extraction. These experiments have shown the dependence of the velocity of ultrasound on the hold-up to be given by Eq. (7) as well as its dependence on the size of the droplets forming the dispersion. Further the experiments have revealed no interaction between the effect of the hold-up and a third component dissolved in the liquids on the velocity of ultrasound in the dispersion. The net effect may thus be computed by the additivity rule. Thanks to its simplicity and reliability the method is suitable not only for laboratory measurements but also for monitoring hold-up in large scale industrial equipment.