Application and prospect of titanium - part 2

Titanium and its alloys are not only widely used in aviation and aerospace industry, but also in chemical industry, petroleum, metallurgy, paper making, textile, machinery and energy; Medical and health industries also have very important applications. 

The application of titanium in civil industry is also increasing

(1) The utilization of coal gangue is a pioneering effort to turn waste into treasure. Coal gangue is a waste in coal mining, which is estimated to be hundreds of millions of tons in China. China has been using coal gangue to produce aluminum chloride or aluminum sulfate since 1972. In the renewal process, the corrosion of stainless steel concentrator is quite serious. China's self-made titanium reactor, agitator, coil heater (for aluminum chloride) and concentration heater (for aluminum sulfate) have been operating for more than ten years.  

(2) Thin walled titanium tubes for condensers in coastal power plants. As early as the 1960s, Britain had used all titanium condensers. In the 1970s, Japan introduced thin-walled (0.3-0.5mm) titanium tube welded condensers, which greatly reduced the cost. Till 1987, 30% of industrial developed countries had adopted titanium condenser. Due to the high requirements for safe operation reliability of nuclear power plants, special attention is paid to the use of titanium condensers, most of which are thin-walled welded titanium tubes and seamless titanium tubes. China began to test domestic titanium tubes in the late 1970s. Since 1983, 18 all titanium condensers have been used in 9 power plants, including Taizhou Power Plant in Zhejiang Province, Jinshan Thermal Power Plant in Shanghai, and Zhenhai Power Plant in Zhejiang Province, sharing 700t titanium tubes. The application effect is very satisfactory.    

(3) In oil and gas drilling and production, Britain has used titanium drilling and production equipment in the depth of 600m, 262 ℃ and 5% H2S and 25% NaCl. The former Soviet Union adopted titanium pumps, titanium valves and titanium washing brine equipment. In order to solve the corrosion of high-temperature H2S, C02 and steam at 600-700 atm, Ti-6Al-4V valve plate, valve seat and valve stem are used at natural gas wellhead in China, and the long-term use effect is very good.        

(4) Offshore oil and gas exploitation should bear seawater corrosion and stress corrosion for a long time. Ti-6Al-4V is widely used abroad as oil platform support, rope support, high-pressure pump, riser and coupler of seawater circulating pressurization system, etc. Because Ti-6A1-4V is not only resistant to seawater corrosion, but also has high toughness, high yield strength and high fatigue limit. Recently, titanium pre-stressed oil production pipe joint has been selected abroad. This joint is easy to assemble, light in weight, and maintains elastic sealing. Titanium is the best material. China's offshore oil industry is entering the stage of large-scale development. At present, the structure, key components and equipment of the platform are imported from abroad, and domestic materials are rarely used. However, it can be expected that titanium will find a broad market here.  

(5) The operating temperature of the radioactive waste evaporator in the nuclear power plant is higher than 130 ℃, and there is a possibility of crevice corrosion due to sediment during concentration. Therefore, the best material of evaporator should be Ti-6Al-4V, and Ti-15Al-2.5Sn can be selected under high pressure.

(6) The turbine blade of steam turbine was originally made of 0Crl3 stainless steel. Due to the crevice corrosion and pitting corrosion in the sediment, the fatigue life decreased. Titanium alloy is the most ideal material. The former Soviet Union developed Ti-5Al-2.5Sn long steam turbine blades, which have been widely used in production. In recent years, the United States, Japan and other countries tend to use Ti-6Al-4V.      

(7) Titanium equipment and titanium anode are ideal materials for desalination device of power plant boiler water, no matter electrodialysis desalination or distillation desalination. Titanium dissolution tank and heater have also been successfully used in the coagulation sedimentation system to remove colloidal impurities in water.      

(8) Application of titanium in chemical industry: titanium has strong corrosion resistance because of its strong affinity for oxygen, which can form a dense oxide film on its surface and protect titanium from medium corrosion. Titanium has strong corrosion resistance in atmosphere, chlorine or other oxygen containing environments, and also has high corrosion resistance in hot salt, hot wet chlorine, hot nitric acid, hot acetic acid and other corrosive media. If the oxide film on titanium surface can be continuously dissolved in a certain medium, titanium will be corroded in this medium. For example, when hot hydrochloric acid and sulfuric acid are added with oxidants or some metal ions, the oxide film on the titanium surface will be protected, thus increasing the stability of titanium. In chlor alkali industry, the anode plate made of titanium metal and the wet chlorine cooler made of titanium have achieved good economic results.