Application of titanium equipments-titanium heat exchangers and titanium coils in petrochemical field

Titanium is the most commonly used industrial pure titanium, with TA2 (US label number Gr2) the most widely used, Ti-6Al -- 4V(when a certain strength is required) and Ti-0.8Ni -- 0.3Mo(when there is a gap or in non-oxidizing media). When hydrogen absorption and embrittlement are possible, especially in the case of weld corrosion and hydrogen absorption, low iron (< .05%) of titanium. Titanium equipment - titanium heat exchanger, condenser and related auxiliary equipment have been successfully used in petrochemical enterprises for more than 20 years.

Terephthalic acid is the raw material of polyester synthesis. Both high temperature oxidation and low temperature oxidation exist high temperature corrosion of acetic acid and bromide. In the medium with temperature higher than 135℃, the pitting corrosion of 316L stainless steel occurs after dozens of hours. Therefore, the design specification stipulates that titanium material must be used above 135℃. Beijing Petrochemical Complex has introduced a complete set of titanium equipment, including 16 sets of oxidation reactor, solvent dehydrating tower, heater, condenser, reboiler, etc. Nanjing Yangzi Petrochemical Company introduced an annual output of 450,000 tons of terephthalic acid equipment, 56 sets of titanium equipment and a large number of titanium pipeline valves. The oxidation reactor introduced by Shanghai Petrochemical Complex is 32m high with an upper diameter of 4m and a lower diameter of 5.3m, with a volume of 505m and a dead weight of 175t. The effect of titanium material is very good and the prospect of popularization and application is bright.

In the ethylene oxidation to acetaldehyde, acetaldehyde oxidation to acetic acid and propylene oxidation to synthesize acetone device, in addition to raw materials and products have a certain corrosion, the main corrosion medium is the catalyst, stainless steel corrosion quickly, only titanium has good corrosion resistance. As early as 1963, titanium was successfully applied in the production of acetaldehyde by oxidation of ethylene in the United States. Our country's first set of ethylene oxidation to produce acetaldehyde was put into use in 1976, titanium equipment has been running well. The titanium lined reactor abroad is up to 9.6m with a diameter of 3m, and there are 11 titanium equipment such as heat exchanger, catalyst regeneration tower and acetaldehyde solution cooler. In the 1980s, Shanghai and Jilin have introduced foreign ethylene oxidation to produce acetaldehyde complete sets of equipment, many of which equipment and pump valves are made of titanium, compared with stainless steel has obvious advantages, the use effect is very satisfactory. The final design of propylene oxidation to acetone, there are 12 sets of titanium equipment, an annual output of 30,000 tons of acetone factory, titanium equipment up to 40t.

Examples of titanium equipment applications in the petroleum industry:

Urea is a high quality fertilizer and a raw material of petrochemical industry. Since the first titanium-lined urea reactor was put into operation in 1963, nearly ten thousand devices have been put into operation in the world, and the practice shows that there is no obvious corrosion in the titanium-lined reactor. The converted corrosion rate of 316L stainless steel is 4.1-4.5mm/a. So titanium has better economic benefits than stainless steel. In addition to lined titanium urea synthesis tower, domestic since the 1970s, has used C02 stripper, heat exchanger, mixer and pump valve.

Titanium equipment is ideal for crude oil refining with high sulfur and salt content. Overseas in atmospheric distillation unit, sewage treatment equipment, desulfurization separation tower condenser and stripping tower radiator and many other processes have successfully used titanium equipment for many years. In the system, our country has also used cast titanium sea water pump, titanium condenser in catalytic cracking, deep-cold separation titanium condenser and porous titanium plate. All of them have been used in the normal operation for ten years.

Chlorinated hydrocarbon is one of the largest varieties in petrochemical industry. Because of the chlorination involved, stainless steel equipment has been incompetent. Titanium materials have been used in the manufacture of dichloromethane distillation column, trichloroethane heat exchanger, condensing column and fractionating column, trichloroethylene condensation column, perchloride heat exchanger and polychloride coil heater. In our country, in the production of vinyl chloride, the Ti-0.2 Pd lining is used for cooling tower, wastewater stripping tower and storage tank plate support frame, nozzle and flange sealing surface, which has not been used for nearly 10 years. Titanium pipes, joints and gas distributors have been used for many years.

Phenol is an important raw material of petrochemical industry. It is a new process to obtain phenol and acetone from isopropylbenzene and isopropylbenzene peroxide using propylene and benzene in oil refining gas as raw materials. Titanium equipment was adopted in foreign countries ten years ago. This technology is still being developed in our country. In the old process to produce phenol with benzylsulfonated alkali solution, titanium neutralization reactor, titanium coil cooler, agitator sleeve and titanium target of ion-titanium nitride have been used in our country. The results are very good.