The Effect of Ozone on the Coating System and Corrosion to Ballast Water Tanks

• Main Authors: Yu Lin Kao, 高幼玲
• Other Authors: Jiunn-Liang Guo
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/25824789368759373393

碩士 === 國立臺灣海洋大學 === 商船學系所 === 98 === In recent years, Aquatic Nuisance Species (ANS) introduced via the ship’s ballast water is becoming an increasingly detrimental ecological issue. Therefore, as a remedy for this shortcoming, a convention — The International Convention for the Control and Management of Ship’s Ballast Water and Sediments 2004 — formulated by the International Maritime Organization (IMO) was established. The convention requires all ships to have a ballast water treatment system installed. Currently, numerous mechanical, physical and chemical treatments are being invented, which may help reduce the ANS phenomenon. Ozone is a possible solution for the sake of alleviating the ANS phenomenon. This paper discusses the effects of ozone on the coatings and corrosion of ships. Simulation experiments on the ballast water system were conducted, which included the bulkhead of the tank and piping system. A plastic bottle (150ml) was filled with seawater, along with four different concentrations of ozone (0 ppm / 10 ppm / 15 ppm / 20 ppm). Two fully-coated branded specimens and steel plates were then placed within the bottle for testing purposes. Some results were obtained: (1) Discoloration of the epoxy coating and a dramatic change of the surface texture were observed in the presence of ozone. The measured pH value ranged from 6 to 8, which was tolerable. (2) Corrosion rates were increased under higher ozone concentration ratios and higher corrosion rates were distinct during early weeks of the experiment period, which was eight weeks long. (3) Based on the method of Multiple Regress. It was concluded that a positive correlation exists between ozone concentration and corrosion rate, and a negative correlation exists between length of time and corrosion rate. In summary, there are no noticeable effects on the coating system if ship’s ballast water is treated with ozone, but there are concerns regarding the corrosion of steel plates.