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DOI : 10.17640/KSWST.2017.25.4.21 ,    Vol.25, No.4, 21 ~ 30, 2017
Title
A Study On Oxygen Transfer Characterization by Using a h-Type Air Supply Equipment Pursuant to Gas-Liquid Film
조용현 Yong-hyun Cho , 김연은 Yun-eun Kim , 김희영 Hee-young Kim
Abstract
In this study, the aeration system using the principle of airlift pump, which is one of the element technologies for the artificial aeration, was researched as part of the measures to prevent the eutrophication in the lentic zone and the oxygen depletion in the bottom water. The mass transfer characteristics of the oxygen such as oxygen transfer variation, changes in DO concentration, dissolution, overall oxygen mass transfer coefficient(KLa), oxygen dissolution efficiency(EA), etc. were evaluated through the h-type liquid-film air supply unit, which has oxygen dissolution and water circulation functions and the oxygen supply function by the liquid film. In the results of water circulation experiment with the deoxygenated water of having DO of 0.5 mg/L or less at air supply of 17 L/min, 20 L/min, 23 L/min and 26 L/min, it was judged that operating at 23 L/min was appropriate. The DO concentration by air supply at 14℃ and 17℃ of the water temperature was measured and the performance of the aeration system was evaluated by calculating KLa and EA considering the air flow rate, water temperature and reactor size out of the various factors having impact on the oxygen transfer. In the results of calculating KLa(20), the more the air supply was increased by 23 L/min, the more the value was increased but at 27 L/min, it showed the tendency that it was increased slightly or decreased. In the results of calculating EA, which is the basic index of aeration efficiency, the more the air supply was increased, the pure oxygen dissolution efficiency was decreased. Therefore, it was observed that in the aspect of water circulation, it did not require the air supply more than necessary. In addition, in the aspect of oxygen supply, the more the air supply was increased, the more the aeration efficiency of the system was decreased, which is deemed that the formation of liquid-film was inhibited.
Key Words
rlift Pump, Liquid Film, Oxygen Transfer Coefficient, Aerator, Standard Oxygen Transfer Rate
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