What Are The Advantages Of Titanium Tubes in Power Plant Applications?

Through a large number of experiments and application examples, it has been proven that the application of titanium tubes in power plant condensers has great technological and economic advantages. From an economic perspective, taking the price of pipelines (approximately 50000 condenser tubes) for a 1000mw condenser in Japan in 1983 as an example, based on the 40 year service life of the condenser, the average annual leakage of aluminum yellow tubes is 40 years. Three issues that should be addressed when applying titanium tubes to power plants:
1. Corrosion issues
Seawater is used as cooling water for condensers in coastal power plants. Due to the presence of a large amount of sediment, suspended solids, marine organisms, and various corrosive substances in seawater, the situation becomes more severe in brackish water where seawater and river water alternate. The corrosion methods of traditional copper platform metal pipes include overall corrosion (uniform corrosion), erosion, stress corrosion, etc. Titanium has excellent corrosion resistance. Titanium tube condensers eliminate seawater leakage accidents due to corrosion, but they have good corrosion resistance. Unlike copper alloy tubes, which produce toxic substances on the surface, the inner walls of titanium tubes are prone to attachment of marine organisms, which affects heat transfer efficiency and requires corresponding cleaning devices.
2. Hydrogen absorption problem
Although titanium has a dense passivation film on its surface and is highly corrosion-resistant in many highly corrosive media, it has a high affinity for hydrogen. Very easy to absorb hydrogen. It occurs at room temperature and rapidly absorbs hydrogen at high temperatures (such as 100 ℃). The solid melting limit of hydrogen in titanium is very small (about 20ppm), and beyond the limit, hydrides (TtH2) will precipitate on the surface of titanium. As the surface TiH2 content increases, the impact value and elongation of titanium rapidly decrease at 4j. In addition, during the renovation of the old unit, due to the use of copper alloy for the tube plate and titanium for the condenser tube, cathodic protection devices are needed to prevent electrochemical corrosion. For example, the condenser of Hitachi power plant is cooled by seawater, and a thermocouple is composed of titanium tubes and copper alloy plates. When the protection potential is below 0.75V (SCE), the outlet titanium tube end absorbs hydrogen gas, and the hydrogen content reaches 650ppm after one year of use; If the potential is 0.5-0.75V (SCE), titanium will not absorb hydrogen at room temperature.
3. Vibration issues
Due to the good corrosion resistance of titanium pipes. Titanium solidifiers will not leak due to corrosion. However, titanium tubes may be damaged due to vibration. In order to avoid vibration problems of titanium tubes, it is necessary to determine the appropriate partition spacing when manufacturing shielded titanium solidifiers. When renovating old units, it is necessary to check whether the original partition spacing is suitable.