Application of industrially pure titanium in the chemical industry

Titanium alloy has excellent corrosion resistance and mechanical properties, and is widely used in many sectors. Especially in the application of chemical industry, titanium can replace stainless steel as a corrosion-resistant material, which is very important for extending the service life of equipment, reducing costs, preventing pollution and improving productivity.

In recent years, China's titanium application in the chemical industry is expanding, titanium dosage increases year by year. Titanium has become one of the main anti-corrosion materials for chemical equipment. As a corrosion-resistant structural material used in chemical plants, titanium has become an ideal material in chemical equipment.

Chlor-alkali industry

Chlor-alkali industry is an important basic raw material industry, and its production and development have a great impact on the national economy. This is because the corrosion resistance of titanium to chloride ions is better than stainless steel and other non-ferrous metals. At present, titanium is widely used in the chlor-alkali industry to manufacture titanium anode electrolyzer and ionic membrane electrolyzer, wet chlorine cooler, refined brine preheater, chlorine dechlorination cooling tower, scrubber tower and so on. The main components of these devices used to use non-metallic materials (such as graphite, PVC, etc.), due to the mechanical properties of metal materials, thermal stability and processing technology performance is not ideal, resulting in bulky equipment, high energy consumption, the use of short service life, and affect the quality of products and environmental pollution. Therefore, from the 1970s, China began to use metal anode electrodes and ionic membrane bath instead of graphite electrodes, titanium wet chlorine cooler instead of graphite cooler, have achieved good results.

For example, the application of titanium wet chlorine cooler. The production of caustic soda is to produce a large number of high-temperature wet chlorine gas, the temperature is generally 75 ~ 95 degrees Celsius, need to be cooled and dried to use. China's electrolytic chlorine process is unreasonable or cooling equipment corrosion affects chlorine yield and quality, serious environmental pollution. High-temperature wet chlorine corrosion of titanium cooler put into production, changing the production prospects of the chlor-alkali manufacturing industry. Titanium in the high temperature wet chlorine environment is very resistant to corrosion, chlorine titanium at room temperature at 80 ℃ corrosion rate of 0.000565mm / a; chlorine water, titanium corrosion rate of 0.00431mm / a; containing 95% wet chlorine, titanium corrosion rate at room temperature of 0.00096mm / a. Many commonly used Chlor-Alkali Titanium Wet Chlorine Cooler, some of which have been in use for nearly 20 years, and is still intact! .

Soda Industry

Soda ash is one of the most basic chemical raw materials, which is directly related to the development of the national economy. Sodium carbide production process, the gas medium for NH3 and CO2, the liquid medium for the high concentration of NaCl, NH4Cl, NH4HCO3 and Cl- solution, the use of steel and cast iron material carbide tower tubular cooler, cooler, cooling, cooling, liquid crystal outside the cooler of the main equipment is not corrosive, corrosion leakage is serious, the service life of not more than three years. 1975-1977, Tianjin Soda Plant and Dalian Chemical Industry Construction Company for titanium application demonstration work, the application effect of carbonization tower cooling tube 63 × 2mm, titanium plate, titanium heat exchanger outside the cooler, titanium pumps, CO2 turbine compressor rotor, titanium - 6Al-4V alloy impellers are very good, which for the industry with titanium technology transformation and the construction of three new 600,000 tons of annual output of pure soda ash plant played a demonstration role.

For example, the alkali plant distillation tower ammonia condenser application of pure titanium pipe instead of cast iron pipe. Ammonia condenser is the production of sodium carbonate process, ammonia distillation tower distillation condensation equipment, it consists of two cast iron cooling box, each box diameter 2.5m, 1.2m high, the original Φ63 * 6 * 2986mm cast iron tubular 214, two boxes 428. Tube inside and outside are preserved by thermosetting phenolic varnish, the external medium is NH3, CO2, H2O vapor, temperature is 95 ℃. Pipe NH4Cl mother liquor, heat exchanger and piping medium. In this case, the cast iron pipe corrosion is serious, the use of a year that is part of the pipe corrosion perforation, 2 years corrosion damage is serious, stop using. In order to solve the serious corrosion problem of cast iron pipe in the ammonia condenser, all cast iron pipes are replaced with TA2 titanium pipes with specifications of Φ60*2*3010mm, and O-type rubber sealing ring is used for the end of titanium pipe and cast iron flower plate. This is China's first industrial soda ash cooling tubular distillation tower, made of pure titanium tube. Put into operation for more than two years, has been a macro inspection of the pumping pipe, no corrosion phenomenon, is expected to service life of up to 20 years, 10 times longer than the cast iron pipe. As the titanium tube corrosion resistance, heat transfer efficiency is good (cast iron pipe in 3 years during the overhaul of the heat transfer efficiency of early, middle and late failure), NH4Cl tube preheating heat recovery heat energy to improve the white liquid, the white liquid into the distillation temperature, can save a lot of steam, the economic benefits are obvious.