Although titanium has a dense passivation film on its surface and is highly resistant to corrosion in many highly corrosive media, it has a strong affinity for hydrogen. It’s very easy to draw hydrogen. Occurs at room temperature, and at high temperatures (such as 100℃) hydrogen uptake is rapid. The fixation limit of hydrogen in titanium is very small (about 20ppm), beyond which hydride (TtH2) will precipitate on the surface of titanium. Along with the increase in surface TiH2, titanium impact value and elongation reduced quickly.
In addition, the transformation of old units, due to the tube sheet is copper alloy, titanium condensation works, this would require the use of cathodic protection devices to prevent electrochemical corrosion such as Hitachi plant condensate gas with water cooling, column pipe and copper alloy titanium plate of galvanic couple, when the protection potential is less than a 0.75 v (ScE) make export titanium pipe end hydrogen absorption, use the hydrogen content of 650 PPM a year; if the potential to choose a 05 ~ o. 75 v (ScE), titanium is not going to happen at room temperature hydrogen absorption”