EVALUATION OF EFFICIENCY OF GAS-LIQUID APPARATUS WITH EJECTION GAS DISPERSION

Abstract

Various constructions of gas-liquid dispersion devices with gas ejection which can be used to implement many of the processes taking place in the gas - liquid system are compared. Experimental methods for comparative evaluation of the efficiency of gas-liquid ejection apparatuses of various designs are considered. Three constructions of gas-liquid dispersion devices with ejection of gas were investigated: the gas-liquid jet apparatus, short ejector apparatus with a long ejector, and apparatus with combined (multilevel) ejector. Evaluation of efficiency was performed with two ways: chemical and photographic techniques. The chemical method is based on determining the effective phase contact surface, which was estimated using the "sulphite number" of oxygen chemisorption from air. With the help of the photographic method the efficiency ratio was determined which takes into account not only the rate of the process, but also the energy costs of its conduction. The smaller value of the coefficient of efficiency the apparatus operates efficiently, i.e. for a specific interfacial surface requires less energy. Experimental studies were carried out in an apparatus with a diameter of 200 mm for a variety of pressure at the nozzle and diameter of the nozzle. The pressure at the nozzle was varied from 0.2 to 0.4 MPa, and the diameter of the nozzle - from 2 to 4 mm. For each experiment the "sulfite number" was determined and further the criterion of efficiency of gas-liquid system was calculated on the experimental data. Graphic dependences of "sulphite number" and coefficient of efficiency are presented for the differential pressure at the nozzle for three examined constructions of gas-liquid vehicles with the gas ejection. The findings on the effectiveness of devices using gas-liquid "sulfide method" and the efficiency ratio are in good agreement. For devices with a long ejector and ejector combined with coefficients of similar efficiencies, but these devices are much more efficient than the gas-liquid jet apparatus and the short ejector. On the values of «sulphite number" the device with a combined ejector is the most effective. This is due to the fact that in this device there is mass transfer intensification by increasing the contact surface and contact time of the interacting phases.