Abstract
The possibility to disintegrate bubbles and to accelerate gas-liquid reactions has been investigated by applying ultrasonic vibration to the injection nozzle in water model experiment. The formation of fine bubbles was examined by visual observation. The acceleration effect was examined in absorption of CO2 to NaOH solution and distilled water, and desorption of CO2 from the latter solution. The bubbles were disintegrated by the application of ultrasonic vibration. The effect was remarkable at low gas injection rate. At high gas injection rate, however, large bubbles were formed discontinuously along with the fine bubbles formation. The fine bubbles penetrated deeper into the solution due to the jet stream induced by the ultrasonic vibration. All of the above gas-liquid reactions were accelerated by the application of ultrasonic vibration. This was attributed both to the larger interfacial area caused by the disintegration of bubbles and to longer residence time of bubbles in the solution. The mechanism of the disintegration is considered as follows : in the negative pressure period of vibration, cavities are formed in the vicinity of nozzle tip, where some amount of gas penetrate into, then the gas is disintegrated into fine bubbles in high pressure period of vibration. There existed the optimum nozzle dimension to accelerate the reaction, which was determined by compromise between linear velocity of gas and amplification of vibration at nozzle tip.
