What Are The Advantages Of Gr2 Seamless Titanium Tubes in Power Station Applications?

Through a large number of experiments and application examples, it has been proved that the application of titanium tubes in power station condenser has great superiority both technically and economically. From the economic point of view, in 1983, Japan's 1000mw condenser nuclear power plant piping (about 50,000 condenser tubes) prices, for example, according to the condenser's use of 40 years, the average annual leakage of aluminum yellow tubes is 40 years. Three problems that should be solved by the application of titanium tubes in power stations.
1. Corrosion problems

Seawater is used as cooling water for condensers in coastal power stations. As seawater contains a large amount of sediment, suspended solids, marine organisms and a variety of corrosive substances, the situation is more serious in the brackish water alternating between seawater and river water. Traditional copper platform metal tube corrosion methods are: overall corrosion (uniform corrosion), erosion, stress corrosion and so on. Titanium has excellent corrosion resistance, titanium tube condenser due to corrosion to eliminate seawater leakage accidents, but good corrosion resistance, unlike copper alloy tubes as the surface of the production of toxic substances, titanium tubes are easy to adhere to the inner wall of the sea organisms, affecting the effect of heat transfer, the need for the corresponding cleaning device.

2. Hydrogen absorption

Although the surface of titanium has a dense passivation film, in many strong corrosive media is very corrosion-resistant, but titanium and hydrogen have a high affinity. Very easy to absorb hydrogen. Occurs at room temperature, high temperature (such as 100 ℃) hydrogen absorption rapidly. The solid fusion limit of hydrogen in titanium is very small (about 20 ppm), and above the limit, hydride (TtH2) precipitates on the surface of titanium. With the increase of TiH2 content on the surface, the impact value and elongation of titanium at 4j decreases rapidly. In addition, when old units are retrofitted, cathodic protection devices are required to prevent galvanic corrosion because copper alloys are used for the tube sheets and titanium is used for the condenser tubes. For example, the condenser at Hitachi Power Plant is seawater cooled, and the titanium tubes and copper alloy plates form a thermocouple. When the protection potential is lower than 0.75V (SCE), the exit titanium tube end absorbs hydrogen, hydrogen content of 650ppm after one year of use; if the potential is 0.5 ~ 0.75V (SCE), titanium at room temperature will not absorb hydrogen.

3.Vibration problem

Due to the good corrosion resistance of titanium tube. Titanium coagulators do not leak due to corrosion. However, there is a possibility that the titanium tube may be damaged due to vibration. In order to avoid the problem of vibration of titanium tubes, in the manufacture of shielded titanium coagulators, it is necessary to determine the appropriate spacer spacing of the old unit remodeling, it is necessary to check whether the original spacer spacing is applicable.