A MODEL FOR SIMULTANEOUS MEASUREMENT OF GAS AND SOLID HOLDUPS IN A BUBBLE-COLUMN USING ULTRASONIC METHOD

The ultrasonic method developed to measure the dispersed phase holdups in dispersion systems is based on the fact that the velocity of ultra sound in the dispersion is different from that in the liquid. The rela tionships between velocity differences in the term of transmission tim e differences of ultrasound and gas holdup in a gas-liquid system and solid holdup in a liquid-solid system were derived. The holdups became linearly dependent on the time differences, which is in agreement wit h the experimental data. Based on those relations, a model for simulta neous measurement of gas and solid holdups in three-phase systems is p roposed. The model permits measurement of the dispersed phase holdups by measuring the transmission time of ultrasound transmitted through t he dispersions in two frequencies. It allows investigation of local ho ldups distributions in a bubble column and in a suspended bubble colum n.