Waste Water Purification on the Freezing Phenomenon of Falling Film on Inclined Plane

• Main Author: 黃新武
• Other Authors: 周賢福
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/11396392904469847308

碩士 === 國立臺灣大學 === 機械工程學研究所 === 87 === As conventional process for treating waste water can not meet the stringent requirement of the environment protection gradually, a more efficient way of treatment is needed. Since the freezing operation of falling film has many advantages, including very high heat and mass transfer, it could possibly offer a more effective and economical method for the issue. The objective of the present study is to perform an experimental investigation on the controlling parameters associated with the freezing phenomenon of falling film, including the flow rate, the inlet temperature, and the inlet concentration of the waste water, the flow rate and the inlet temperature of the refrigerant, the time of ice formation, the inclined angle of the heat transfer plane, and the effect of pre-existing nucleus of crystallization. Optimal running conditions for treating the waste water is to be found. The results of the experimental studies show that the lower the heat transfer rate, the higher the degree of purification. However, degree of purification will decrease when the heat transfer rate is much too low. If the surface of the plate is wetted completely, then reducing the flow rate and inlet temperature of the waste water as far as possible, and increasing the time of ice formation suitably will not only get more quantity of ice formation but also improve the quality of ice formation. With pre-existing nucleus of ice crystal on the surface will result the same trend. Although reduction of the inclined angle of the heat transfer plane has negative effect on the quantity of ice formation, it can improve the degree of purification effectively.