Anti-corrosion of Titanium Materials in the Power Industry

Titanium has good stability in strong corrosive hot water containing chlorides and sulfides, so it has been widely used as cooling tubes for heat exchangers in thermal power plants. With thin-walled titanium tube instead of copper-nickel alloy tube, not only greatly improve the service life, and overhaul time is greatly reduced, the economic benefits are significant.

Titanium and titanium alloys have good corrosion resistance and can also be used for anti-corrosion lining of steel chimneys. A seawater desulfurization system without GGH and bypass is used in Jetvision. Titanium plates are used as anti-corrosion lining for steel chimneys in wet chimneys.

Industrially pure titanium is a thermodynamically unstable metal. The standard electrode potential for titanium ionization is -1. 63 V if Ti2 + can be produced by dissolution, which makes titanium soluble in water and releases hydrogen. However, titanium is very resistant to corrosion in a wide range of corrosive media due to its large passivation. Its passivation exceeds that of cobalt, nickel and stainless steel. It has excellent corrosion resistance in many reactive media, especially in oxidizing media, chlorine and chloride media, but titanium is poorly stabilized in sulfuric and hydrochloric acids. In order to solve the problem of poor corrosion resistance of conventional titanium and titanium alloys to reducing media such as sulfuric acid and hydrochloric acid, the addition of molybdenum (10% 32%) in titanium alloys can greatly improve the corrosion resistance of titanium alloys to reducing media. The higher the molybdenum content, the better the corrosion resistance, but the more difficult the smelting and processing. The main performance is the strengthening of the alloy, to a certain extent, affecting the application of the alloy. Titanium-molybdenum alloys are more suitable for corrosion protection of steel chimneys than pure titanium. titanium-molybdenum alloys of Ti-20MO and above meet the requirements and, because of their high resistance to chlorides, are particularly suitable for power plants using seawater desulphurization. 

Titanium coils are used for condensers in coastal power stations. Aluminum brass tubes or B30 white brass tubes were used until the 1960s. With the increase of seawater pollution, the service life was greatly reduced. All titanium condensers were used in the UK as early as the 1960s. thin-walled (0.3-0.5mm) welded titanium tube condensers were introduced in Japan in the 1970s at a much reduced cost. titanium condensers were used in 30% of developed countries by 1987. The use of titanium condensers has been particularly emphasized due to the high demands placed on the safe operation and reliability of nuclear power plants. Most of them use thin-walled welded titanium tubes and seamless titanium tubes.