The application of titanium equipment in soda industry has good results

Soda ash is one of the most basic chemical raw materials, which is directly related to the development of national economy. In the process of soda ash production, the gas medium is mostly NH3 and CO2, and the liquid medium is mostly the solution of NaCl, NH4Cl, NH4HCO3 and Cl- with high concentration. The carbonization tower tubes, hot mother liquid coolers, coolers, crystallizing external coolers and other main equipment using carbon steel and cast iron materials for carbonation reaction are not corrosion resistant, and the corrosion leakage is serious. Service life is not more than three years. From 1975 to 1977, Tianjin Alkali Plant and Dalian Chemical Industry Company built plants for titanium application demonstration work, carbonization tower cooling pipe 63×2mm, titanium plate heat exchanger, titanium external cooler, titanium pump, CO2 turbine compressor rotor, Ti-6Al-4V alloy impeller, etc., the application effect is very good. This has played a model role in the transformation of titanium technology for the whole industry and the construction of three new soda plants with an annual output of 600,000 tons.

For example, the ammonia condenser at the top of the distillation tower of a soda plant uses pure titanium tubes instead of cast iron tubes. Ammonia condenser is a equipment for condensing the ammonia vapor from the distillation tower in the process of soda ash production. It is composed of two cast iron cooling boxes, each box has a diameter of 2.5m and a height of 1.2m. The original box contains 214 cast iron tubes of Φ63×6×2986mm, and the two boxes have 428. Both inside and outside the pipe are anticorrosive with thermosetting phenolic varnish. The medium outside the pipe is NH3, CO2, H2O vapor, and the temperature is about 95℃. The NH4Cl mother liquor is carried through the pipe to exchange heat with the medium outside the pipe. Under this condition, the cast iron pipe is seriously corroded, and some pipes are corroded and perforated within a year of use, and the corrosion damage is serious in 2 years, and the use is stopped. In order to solve the serious corrosion problem of cast iron pipes in ammonia condenser, all cast iron pipes are replaced with TA2 titanium pipes, Φ60×2×3010mm, and O-shaped rubber rings are used to seal the end of titanium pipes and cast iron panels. This is the first distillation column cooling tube in China's soda ash industry using pure titanium tube. Put into operation for more than two years, the pipe has been pumped for macroscopic inspection, no corrosion phenomenon was found, and the service life is expected to reach more than 20 years, which is 10 times longer than that of cast iron pipe. Due to the corrosion resistance of the titanium pipe, the heat transfer efficiency is maintained well (the cast iron pipe in a three-year overhaul period, the heat transfer efficiency is good in the early stage, poor in the middle stage, and the failure in the later stage), the NH4Cl mother liquor in the pipe is preheated to recover heat, improve the temperature of the mother liquor entering the distillation tower, which can save a lot of steam and has obvious economic benefits.