Baoji Tongrun Metal materials Co., Ltd.


    Seawater treatment

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    Update time : 2023-09-14



    There are generally two methods of seawater desalination: distillation and reverse osmosis. The former is to heat seawater to vaporize it, and then condense the steam to obtain fresh water; the latter is to pressurize seawater and allow the freshwater in it to pass through a special The membrane traps the salt and obtains fresh water. Judging from the development of seawater desalination abroad and the use of titanium, the distillation method has a higher working temperature and uses titanium; the reverse osmosis method works at a lower temperature and usually does not require titanium. Distillation accounts for 75% of the world's seawater desalination methods, and reverse osmosis accounts for 20%. In chlorine-containing media such as seawater and salt water, carbon steel, low alloy steel, general stainless steel, and aluminum have poor corrosion resistance, while titanium has unique and excellent corrosion resistance. About 50% of titanium equipment is used to resist corrosion containing Corrosion in chlorine media.

    Because titanium has excellent corrosion resistance, mechanical properties and process properties, it is widely used in many parts. Especially in chemical production, titanium is used to replace stainless steel, nickel-based alloys and other rare metals as corrosion-resistant materials, which can increase output value, improve product quality, extend equipment service life, reduce consumption, reduce energy consumption, reduce costs, and avoid pollution. , improving working conditions and increasing productivity are of very important significance. In recent years, the scope of titanium used in China's chemical industry has continued to expand, and its usage has increased year by year. Titanium has become one of the important anti-corrosion materials in chemical equipment. As a corrosion-resistant structural material used in chemical equipment, titanium has established its position, and as an ideal material in chemical equipment, titanium has increasingly attracted the attention of engineering and technical personnel.

    Titanium's ability to resist seawater corrosion is better than that of all other metals. Industrial pure titanium did not show any corrosion after being parked in the ocean at a depth of more than a mile (1.6km) for many years. Although a layer of marine attachments accumulated on the surface of the titanium, However, pitting corrosion and crevice corrosion did not occur. Titanium has special stability whether in stationary or high-speed seawater, while copper alloys or aluminum alloys will corrode very quickly when the seawater flow rate reaches 120 feet/second (36.6m/s), so Titanium is considered one of the best corrosion-resistant materials suitable for use in seawater today. Gr1 and Gr2 titanium alloys (TA1 and TA2) do not cause stress corrosion in seawater; TC4 (Ti-6AL-4V) titanium alloy containing a small amount of oxygen is one of the best high-strength titanium alloys suitable for working in seawater environments. Therefore, titanium is an excellent material for seawater desalination equipment, and titanium will be increasingly used in this field.

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