Titanium began to be used for industrial applications ever since the 1950s, despite the fact that, at that moment, it was considered to be an expensive metal (in comparison to other common choices, such as aluminum or stainless steel). However, the metal gradually gained recognition, being lighter than steel and stronger than aluminum. In the chemical industry, titanium was especially preferred for its excellent corrosion resistance. Today, titanium has become a standard metal used in chemical processing and subsequent industries.
As you will have the opportunity to read below, titanium is a often used for the development of chemical processing equipment, including titanium containers, heat exchangers and titanium anodes. It is often used for the manufacturing of chemical processing equipment, especially in relation to the sodium carbonate and chlor-alkali industries. As opposed to steel, aluminum or other non-ferrous metals, it does not present the risk of corrosion damage and it can represent a highly efficient alternative for chemical plants.
The excellent corrosion resistance of titanium is guaranteed by the unique properties that this metal possesses. The metal is capable of forming and maintaining a protective film, especially in the presence of oxygen (stable oxide). Moreover, the facile metal polarization contributes to the high corrosion resistance. These properties have turned titanium into a preferred choice by those working in the chemical industry; welded titanium pipes, for example, have become a standard in this industry, given the resistance to corrosion damage.
Gradually, the chemical industry has become one of the largest consumers of titanium; the corrosion resistance is, of course, the main reason behind this choice, especially when titanium is used in the presence of oxidizing acids. Perhaps one of the most interesting characteristics of titanium is its ability to form this stable oxide, almost instantly, upon being exposed to air. The corrosion resistance, due to the stable oxide, makes titanium superior to aluminum and steel alloys. These alloys corrode quite easily, increasing the risk for cracks and other damage; such risks are not present with titanium applications. Titanium and titanium alloys are recognized for their high resistance, being often presented as highly-efficient anti-corrosion materials.
The chlor-alkali industry has benefitted tremendously from the usage of titanium, as anti-corrosion material. It was discovered that the titanium chloride ions possessed superior corrosion resistance, especially when compared to other non-ferrous metals, such as aluminum or stainless steel. For this reason, titanium began to be used for the manufacturing of metal anodes and other processing equipment in the chemical industry. Today, wet chlorine coolers, ion exchange membrane electrolyzers, dechlorination towers and chlorine cooling scrubbers rely on the usage of titanium. In fact, it was in the 1970s that titanium replaced the commonly-used graphite for such applications, delivering better results.
Titanium is used for the development of wet chlorine coolers, given its excellent corrosion resistance, despite the high temperatures of the wet chlorine environment. Thanks to its unique properties, titanium is increasingly used in the soda ash production process. Soda ash is one of the most basic raw materials and its production often requires a hot liquid cooler; however, the materials that were previously used for this kind of equipment presented a high corrosion risk. This reduced the service life of the hot liquid cooler to under three years, leading to increased operating and processing costs.
Apart from the cooling pipes, titanium is used for external cooling, pumps and heat exchangers. It is considered a technical innovation and one that has increased the output for the soda ash production process. In China, which is one of the largest consumers of titanium for the chemical industry, titanium was used for the development of the first distillation tower cooling tube. The usage of titanium eliminated the corrosion phenomenon, extending the service life of the equipment from 10 to 20 years (previously, cast iron pipes were used for such equipment). Titanium tubes were chosen not only with regard to the excellent corrosion resistance but also because of the heat transfer efficiency (economical benefits to be taken into consideration).
Titanium is, without any doubt, one of the most economically efficient materials to be used in the chemical industry. It is particularly suitable to highly corrosive environments, presenting, as it was already highlighted, excellent corrosion resistance. It is often chosen because it can extend the service life of chemical processing equipment and also to keep maintenance costs at a reduced level. The chemical processing industry has changed tremendously since the introduction of titanium, especially with regard to the processing of aggressive compounds (hydrogen sulfide, chlorine dioxide, organic acids, nitric acid, inhibited reducing acids etc.). Piping systems, coolers, vessels, heat exchangers, tanks and agitators – these are all equipment pieces for which titanium is used.
The protective oxide layer is what makes titanium stable and resistant to corrosion. As it was mentioned above, this layer forms with exposure to air or, in some situations, to moisture. Moreover, when oxidizing conditions are present, the development of this protective layer is accelerated. Titanium has self-healing abilities in the presence of oxygen, which makes it even more suitable for the chemical processing industry applications.
Titanium remains a standard choice for chemical industry applications, especially where corrosion resistance is required. It is used for the development of chlorine chemicals, as well as for other chemical compounds, such as nitric acid, sulfuric acid, sea water, phosphoric acid and hydrochloric acid. Titanium presents an excellent corrosion resistance, when used in chlorine gas or other solutions that contain chlorine. As you have seen, it is also used in the chlor-alkali industry, for the development of specialized cells. This includes anodes and cathodes but also bleaching equipment, pressure vessels and heat exchangers. In fact, it can be used for any piece of equipment, which is required for the manufacturing of organic chemicals.
An interesting application of titanium is the one regarding sea water. According to the specialists in the field, titanium maintains its excellent corrosion resistance, including when in sea water and exposed to high temperatures. Sea water titanium tubing is used not only in the chemical industry but also for oil refining and desalination. Other applications of titanium include reactors, columns and condensers.
Titanium is available in different grades and also as alloy. Only certain commercially pure grades and alloys are used for chemical processing, as they present properties that make them suitable for this particular industry. Grade 1 titanium is known for its softness, high ductility and excellent formability. Moreover, it presents a high corrosion resistance and the best impact toughness. It represents a standard choice for the chemical industry,
especially because of the formability and corrosion resistance. It is available as titanium plates and tubing, being used not only for chemical processing but also for the manufacturing of chlorate and development of stable anodes.
Grade 2 titanium presents similar properties with the grade 1 titanium, being a little bit stronger. It has excellent ductility, formability and strength; moreover, it possesses high weldability. It is often used for chemical processing, being available either as titanium bars or sheets. Grade 3 titanium is less used, despite the fact that it is stronger than both grade 1 and grade 2 titanium. It is just as ductile but it presents a reduced formability, in comparison to the other two. It is used for chemical processing, because of its high corrosion resistance and additional mechanical properties.
Titanium alloys are also used in the chemical industry, with G7 being one of the most common choices. It has similar properties with G2, the difference being given by the addition of palladium. The main advantage that G2 has to offer is the high corrosion resistance. It also presents excellent weldability, being perfect for chemical processing (especially in the presence of reducing acids). G11, which presents similar properties to G1, is used for chemical applications in chloride environments. It also contains palladium, as this enhances the level of corrosion resistance. G12 is used for chemical industry applications that present crevice corrosion risks, including for chemical manufacturing at elevated temperatures.