Both high-temperature oxidation and low-temperature oxidation have high-temperature corrosion of acetic acid and bromide. In the medium with temperature higher than 135 ℃, 316L stainless steel will have pitting corrosion after tens of hours. Therefore, the design specification stipulates that titanium must be used above 135 ° C. Beijing Petrochemical plant has introduced a complete set of titanium equipment, including 16 oxidation reactors, solvent dehydration tower, heater, condenser and reboiler. Nanjing Yangzi Petrochemical Company has introduced 450000 tons of terephthalic acid equipment, 56 sets of titanium equipment and a large number of titanium pipeline valves. The imported oxidation reactor has a height of 32m, an upper diameter of 4m, a lower diameter of 5 and 3M, a volume of 505m and a weight of 175t. The effect of using titanium material is very good, and the prospect of popularization and application is broad.
Titanium heat exchanger, condenser and related auxiliary equipment have been successfully applied in petrochemical enterprises for more than 20 years. Among titanium materials, the most commonly used industrial pure titanium (TA2 is the most widely used) and Ti-6Al-4V titanium alloy. When hydrogen absorption and hydrogen embrittlement may occur, especially in the case of weld corrosion and hydrogen absorption, low iron is required. Phenol is an important raw material in petrochemical industry. A new process for preparing phenol and acetone from propylene and benzene, cumene and cumene peroxide. Titanium equipment has been used abroad for more than ten years, but this technology is still developing in China. The old process of titanium equipment uses benzene sulfonated alkali solution to produce phenol. China has adopted titanium neutralization reactor, titanium coil cooler and Ionic Titanium Nitride stirring shaft sleeve, and the effect is very good. Urea is a high-quality fertilizer and petrochemical raw material. Since the first titanium lined urea synthesis tower was put into operation in 1963, nearly 10000 units of equipment have been in operation all over the world. The practice shows that there is no obvious corrosion phenomenon in the titanium lined synthesis tower. The conversion corrosion rate of 316L stainless steel is 4, 1-4 and 5mm / A. Therefore, titanium has better economic benefits than stainless steel. In addition to the titanium lined urea synthesis tower, China has also used CO 2 stripper, heat exchanger, mixer and pump valve since the 1970s.
