Study of the Efficiency and Capability of Aeration Cone in the Recirculating Culture System

• Main Authors: Yi-Feng Su, 蘇一峰
• Other Authors: Chung-Chyi Yu
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/21150039420578240555

碩士 === 國立中興大學 === 農業機械工程學系 === 87 === The aeration cone is the main equipment of pure oxygen absorption system for the recently domestic used water recirculating culture system. The operational control of the aeration cone which controls the Dissolved Oxygen (DO) value of water outlet and the oxygen transfer rate, is mainly by changing the inlet water flowrate and the regulatory valve setting pressure of pure oxygen. In this study, the temperature of water was maintained at about 30℃. When the inlet water flowrate of the aeration cone was controlled between 270-330L/min, the DO value of water outlet would demonstrate a decreasing tendency with the increasing of the inlet water flowrate. When the regulatory valve setting pressure was controlled between 0.35-0.40kg/cm2 (cm square), both of the DO value of water outlet and the oxygen transfer rate would increase as the regulatory valve setting pressure raised. The experimental results showed that the oxygen transfer rate was between 1.137-1.647g/min, the oxygen absorption efficiency was maintained between 72.4-81.5%, the oxygen transfer efficiency was between 0.0681-0.0941kg/kW-hr, the aeration effectiveness was 60.67-70.87%, and the utilization efficiency was maintained between 44.2-58.7%. Furthermore, the relative height between positions of the culture tank and the aeration cone can be designed and planned using Bernoulli's equation. The water lever inside the aeration cone would drop as the regulatory valve setting pressure increased and raise as the inlet water flowrate increased. The water level inside the aeration cone must be kept at least over 60 cm to avoid the water level being too low as the undissolved oxygen inside the aeration cone smuggled with the water flow to the culture tank resulting a waste of oxygen leaking to the atmosphere.