Graphite heat exchanger is a widely used heat exchange equipment in industry. It is mainly used for heat exchange of corrosive media such as sulfuric acid, hydrochloric acid, acetic acid and phosphoric acid. However, in practical application, under the condition of multiple viscous impurities, the resin flakes formed on the surface of graphite lead to increased roughness, resulting in acid sticking to one side of the hole, fouling leads to a sharp decline in heat transfer capacity, and the blockage of graphite pore leads to production line shutdown. These problems are difficult to be effectively solved.
Tantalum material has good corrosion resistance, toughness, ductility and thermal conductivity, and high melting point. Tantalum can be used to replace stainless steel in various inorganic acid production equipment and waste acid concentration equipment, and its service life is dozens of times longer than that of stainless steel. Tantalum also has excellent chemical properties and is highly resistant to corrosion. It does not react with hydrochloric acid, concentrated nitric acid and aqua regia under both hot and cold conditions. When tantalum is immersed in sulfuric acid at 200℃ for one year, the surface damage is only 0.006 mm. Experiments have shown that tantalum has excellent corrosion resistance, similar to glass, and can resist corrosion of almost all chemical media except hydrofluoric acid, fluorine, fuming sulfuric acid and alkali. This rare metal property brings wide space for the application of tantalum.
When the scale thickness of heat exchanger is 1mm, the heat transfer coefficient decreases by about 10%. Therefore, reducing the fouling layer of heat exchanger is the key factor for the long-term stable operation of heat exchanger. The metallic characteristics of tantalum greatly improve the flow rate of acid solution, and the surface of tantalum tube is scoured at high speed. At the same time, the inner surface of tantalum tube is very smooth, and silicon slime is not easy to accumulate, which ensures the efficient and stable operation of heat exchanger. Compared with graphite heat exchanger, tantalum heat exchanger is all welded structure, the overall structure is stable, changing the uncertainty factors caused by graphite brittleness in the lifting and installation process. At the same time, in the cleaning process, there will be no erosion defects similar to graphite because of high pressure erosion. The heat exchanger has been operated stably for 2 months. There is no obvious scaling phenomenon in the process of inspection. The heat exchange is stable. Change the original graphite heat exchanger a month will appear the flow rate, heat transfer efficiency decline. In order to ensure the normal operation of the silicon steel production line, it has brought great positive significance and considerable economic benefits. To sum up, tantalum tube heat exchanger is an excellent heat exchange equipment, which can effectively replace graphite heat exchanger in the pickling of silicon steel. At the same time, due to the machinability of tantalum metal, it can be made into a variety of process equipment, which brings a revolution to the production of organic acid, waste acid concentration and other industrial fields.
