Disinfection in Cooling Tower by Chlorine Dioxide：Performance Evaluation

• Main Authors: Chou, Wen-Cheng, 周文朕
• Other Authors: Huang, Chih-Pin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/c8zdu5

碩士 === 國立交通大學 === 工學院永續環境科技學程 === 101 === The chiller has always been the most powerful consumption operation unit among the factories. One of the most important parameter to remain the chiller operation efficiency is the approach temperature. During the operation, circulating water through cooling towers for heat exchanged is needed, therefore it has become the significantly important to keep good water quality by cooling tower, particularly the total bacterial count. Bacteria growth has become biofilm attached inside copper pipe within heat exchange unit, it will cause not only additional power consumption but also pipe corrosion. Conventionally, sodium hypochlorite (NaOCl) is the mostly used for disinfectants to water treatment since it’s very cheap and easy to access, however, we are short of the research of cooling tower operation by chlorine dioxide in Taiwan. This study is to evaluate how chlorine dioxide (ClO2) to replace sodium hypochlorite. The high-purity chlorine dioxide was produced via a chemical reaction by sodium chlorite and hydrochloric acid reacted. Continuous monitoring and data recording all the time during the trial for water quality, metal pipe line and inside copper pipe of chiller corrosion rate before and after dosing chlorine dioxide. Finally, we are about to evaluate the operation economical benefits via comparisons of cooling towers supply water addition rate and approach temperature variations. The result indicated that high-purity chlorine dioxide is an extremely effective disinfectant; the total bacterial count in the cooling towers is decreased to the level of 5.0Î102 CFU/mL, chiller’s approach temperature is improved and dropped more than 1 ℃ in average. Also it is achieved and saved more than NT$ 1 million/year cost compared to current trial run plant on site.