Waste Water Purification on the Freezing of Falling Film

• Main Authors: Chu, Li-Shiuan, 朱立軒
• Other Authors: Chou Shyan-Fu
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/68662424226275906493

碩士 === 國立臺灣大學 === 機械工程學系 === 85 === Conventional treatment process of the industrial waste water(mainly biological method(is not only a "selective" approach, but also will notmeet the more severe requirement of the environmental protection. Amongthe various possible means, the freezing process is believed to be moreeffective. The present paper is to build an experimental system toinvestigate the controlling parameters involved, including the flow rate, inlet temperature, and inlet concentration of the waste water, the flowrate and inlet temperature of the refrigerant, and the time of ice formation. Furthermore, the effects of pre-existing nucleus of crystallization and in-situ washing of the ice surface are also discussed. If the value of 8 is taken to be the lower limit of the degree of purification, it is found that the inlet temperature of waste water should be smaller than 3oC, and the moderate range of the inlet temperatureof refrigerant is -3oC ~ -4oC. With regard to the quantity of ice formation,there exists an optimum range of the flow rate of the waste water, namelyRe=150 ~ 200. The rate of ice formation has begun to gradually declineas the time of ice formation exceeds 5 minutes. Additionally, the pre-existing nucleus of crystallization has the positive effect on both thequantity of ice formation and degree of purification. The in-situ washingof the ice surface seems to have no pronounced effect on the degree ofpurification.