In 1965, Harvey Aluminum Company of the United States built a seawater desalination plant in the Virgin Islands. Its heat pipes were all made of seamless titanium pipes with a wall thickness of 0.7mm. The total length was 1.85 million meters, about 24 tons, and the daily seawater processing capacity was 1.84 million cubic meters. In 1967, Japan's Songdo Carbon Co., Ltd. built a 2650t/d seawater desalination equipment. The heat transfer tubes and tube sheets of the ventilation condenser and jet compressor of this device cannot be made of copper alloy due to corrosion by bromine (Br) in seawater. After switching to titanium, no failures due to corrosion have occurred. Table 2-44 shows the seawater desalination methods mainly used in Japan.

Fresh water accounts for about 3% of the earth's water resources. Obtaining water resources through seawater desalination is a new trend, especially in the Middle East where water shortage is serious. As early as the 1950s, seawater desalination was used to obtain fresh water. In 1979, 1,468 seawater desalination devices were built around the world. By 1993, 9,014 seawater desalination devices were built in 5,738 regions around the world. In 2004, there were 15,000 desalination units under construction around the world. The main methods of desalination are as follows. ① Evaporation method, single-stage flash evaporation method, multi-stage flash evaporation method, vertical multi-effect method, horizontal multi-effect method, dip tube method, vapor compression method; ② Diaphragm method, electrodialysis method, reverse osmosis method; ③ Composite method. Among them, the evaporation method is the most used, followed by the reverse osmosis method, and the electrodialysis method is used less frequently. Applications of titanium in the marine civil construction industry:

The main problem faced by marine buildings is severe corrosion by seawater and sea salt particles. Titanium has become the material of choice for marine buildings due to its superior corrosion resistance. In the field of marine construction, titanium is mainly used in three categories: ① Anti-corrosion of steel structural parts; ② Corrosion-resistant structural parts; ③ Anti-corrosion of concrete structural parts. Titanium has become the material of choice for marine structures. It has two functions. One is to cover the corrosion-prone parts with titanium sheets; the other is to use titanium steel composite plates for the corrosion-prone parts of marine structures.