The application of titanium in the refining and chemical industry: an excellent choice for corrosion resistance

A reliable material for dealing with water corrosion

Water treatment is an essential part in your refineries. A number of factories are situated close to fresh water supplies but water treatment is necessary to the prevent and mitigate erosion in traditional materials such as carbon steel. But, environmental regulations require that refineries recycle the wastewater, which is usually highly corrosive. To reduce the amount of waste water treatment and diminish the equipment abrasion and maintenance costs induced by corrosion, it is important to select corrosion resistant materials. Titanium's excellent corrosion resistance to corrosive water (i.e. seawater, briny water and wastewater) makes it the best option of water related equipment for the treatment of these water. For example, in some systems involving water circulation and wastewater recovery, the use of titanium materials can effectively extend the service life of equipment and reduce environmental problems such as leaks caused by corrosion.

A sturdy barrier against sulfide corrosion

Crude oil contains a large amount of sulfur, mostly in the form of compounds, with a small amount being hydrogen sulfide (H ₂ S). In oil fields, sulfur is difficult to completely remove. After entering the refinery, some sulfides in the crude oil will be converted into H ₂ S under high temperature heating and high pressure conditions. At the same time, H ₂ S will also be produced through hydrogenation and other catalytic reactions. Sulfidation and pitting corrosion in high-temperature environments, as well as stress corrosion cracking of sulfides, are common and highly destructive forms of corrosion in the refining process. Titanium has a certain resistance to high-temperature sulfurization and pitting corrosion, as well as stress corrosion cracking of sulfides. In the process of petroleum refining, the salt and sulfur in crude oil can cause severe corrosion to stainless steel and copper alloy equipment. Therefore, titanium is needed to make key equipment such as heat exchangers, distillation towers, and reactors for petroleum refining. Titanium pipes are often used for anti-corrosion treatment in the cooling system of petroleum distillation tower tops. When using crude oil distillation technology for high-temperature fractionation of heavy oil to obtain light oil, distillation temperatures above 121 ℃ will convert some chlorine containing substances into hydrochloric acid, while temperatures above 260 ℃ will convert sulfides into highly corrosive hydrogen sulfide. The relevant experimental results show that the use of titanium in condensers and heat exchangers can almost ignore its corrosiveness. Titanium tubes were first applied to the top condenser of crude oil distillation towers in 1960 and have been widely used since then. The combination of titanium tube bundles and tube sheets has been used for many years in the United States and the United Kingdom, effectively reducing the corrosiveness of compounds and greatly extending the service life of refining units.

Corrosion resistance in hydrogenation desulfurization and hydrogen desulfurization

In the process of hydrogenation desulfurization in the refining industry, the temperature needs to be raised to 343 ℃, and then excess hydrogen is discharged from the device through cooling and separation. During this process, the equipment will face corrosion from various corrosive substances such as hydrogen sulfide, hydrogen chloride, and ammonia. Titanium tubes can effectively resist the erosion of these substances, and are therefore widely used in hydrogen production and desulfurization coolers, effectively replacing traditional metals. Getty Oil in the United States extensively used titanium tubes as heat exchangers in 1972, and their corrosion resistance has been fully verified without any problems.

Corrosion resistant tools in acidic gas treatment

Acidic gases must be discharged in refining and chemical production.An aqueous solution of ethanolamine is the most frequently employed adsorbent type, primarily comprising monoethanolamine and diethanolamine, which are adsorbents for hydrogen sulfide and carbon dioxide, respectively. But the reboiler is much more vulnerable to erosion than other parts since the reboiler is a heating equipment. Because of the excellent corrosion resistance of titanium, titanium tube with monoethanolamine reboiler is an excellent combination, which can explainable save the working life of reboiler and make production go on continuously and stably.

Key anti-corrosion measures in the extraction and recycling process

In the extraction technology of the refining and chemical industry, the recovery process can cause significant corrosion. Most of the current extraction techniques use solvents and distillation for separation, followed by a series of extractions in a tower. Some extracts themselves do not corrode, but during the recycling process, a large amount of acid is generated, which has a strong corrosive effect on the environment. A small amount of active compounds such as hydrogen sulfide can also have a certain corrosive effect on the environment. The main corrosion targets are cooling towers and recycling equipment. The anti-corrosion performance of titanium can effectively reduce the corrosion of equipment during extraction. If the enterprise cannot replace titanium alloy equipment in a timely manner, it can also improve the corrosion resistance of the equipment by replacing the main corroded parts or coating the interior of the equipment with titanium alloy.

Corrosion Defender of Catalytic Cracking Unit

The refining and chemical industry is an important link in the daily catalytic and cracking processes that produce corrosive products. There are a large number of sulfides in cr

ude oil, which produce a large amount of hydrogen sulfide and nitrogen compounds during catalysis and cracking processes. These compounds can have a corrosive effect under the action of water. The temperature during the catalysis and cracking process is approximately between 40 ° C and 50 ° C. If the catalytic vessel is mainly made of carbon steel, corrosive compounds will cause balanced corrosion and even "hydrogen cracking" phenomenon on the catalytic vessel. Therefore, adding titanium to the catalytic cracking unit has good corrosion resistance. The United States was the first to use titanium in the refining industry. The Delaware Gedi Refinery in the United States used titanium tube bundles in the fractionator, condenser, secondary condenser, and debutanizer condenser of the catalytic cracking unit, which replaced traditional metals with good results and no corrosion phenomenon was found.