The Application and Advantages of Niobium Tubes in Concentrated Sulfuric Acid Coolers

In the production and processing of concentrated sulfuric acid in the chemical industry, the requirements for equipment corrosion resistance are extremely strict, and traditional materials are difficult to meet the demands. However, niobium tubes stand out with their outstanding performance. Niobium tubes exhibit extremely high corrosion resistance to sulfuric acid. In sulfuric acid with a concentration of ≤70%, the corrosion rate is less than 0.1mm per year. It can remain stable even in 98% concentrated sulfuric acid (≤150°C), and the dense oxide film (Nb₂O₅) formed on its surface further enhances the protective ability. In contrast, the corrosion rate of 316 stainless steel far exceeds that of niobium tubes. Although hafnium alloys are corrosion-resistant, they are costly.

Niobium piping coolers are applied in the form of shell and tube heat exchangers in the concentrated sulfuric acid cooling system. They use pure niobium or nb alloy pipe. Through thin-walled design (1-2 mm thickness), they balance heat conduction and cost. The shell is made of carbon steel or fiberglass reinforced plastic to reduce cost, and the fluid flow direction is optimized, allowing sulfuric acid to pass through the tube side and cooling water to pass through the shell side. In practical applications, after a certain chemical plant replaced the niobium tube equipment, the service life of the cooler was extended from six months to over five years, the heat exchange efficiency increased by approximately 15%, and the maintenance cost was significantly reduced.

However, the application of niobium tubes also faces the challenges of hydrogen embrittlement risk and high cost. Hydrogen embrittlement problems can be addressed by surface palladium or ruthenium plating and controlling the operating temperature. Composite designs (such as niobium-lined steel pipes) can balance performance and budget. With the increasing demand for high-efficiency and long-life equipment in the chemical industry, the application of niobium tubes will further expand, and the research and development of new material technologies is also expected to enhance their stability in extreme environments.

Fortu Tech can produce and process niobium alloys billet, niobium alloys sheet, niobium alloys foil, niobium alloys plate, niobium alloys rod, niobium alloys wire, niobium alloys tubes.