Problem Description:
Graphite heat exchanger is a widely used heat exchange equipment in industry, mainly used for heat exchange of corrosive media such as sulfuric acid, hydrochloric acid, acetic acid and phosphoric acid. However, in practical applications, the working conditions of multi-viscous impurities, the increased roughness of the graphite's surface forming resin flakes leads to acid sticking to the side of the holes, fouling leads to a drastic decrease in heat exchange capacity, and graphite orifice clogging causes production line downtime. These problems are difficult to solve effectively.
A domestic silicon steel cold rolling and acid rolling unit currently utilizes graphite heat exchangers in the pickling process. However, during operation, a significant amount of silica mud accumulates in the acid tank. This, along with clogging in the graphite heaters and other equipment, leads to reduced flow in the acid cleaning circulatory system. As a result, the unit is forced to slow down or shut down frequently to disassemble and clean the graphite heaters, which greatly impacts the unit's normal operation and the working environment. The cleaning process for graphite heat exchangers is complex and time-consuming, requiring complete disassembly of the heat exchanger and drilling out blocked graphite holes. Moreover, graphite is prone to brittle cracking, has low bending and tensile strength, and is susceptible to erosive defects during flushing, causing equipment damage. The entire disassembly, cleaning, and assembly process takes 3-5 days, which has a significant economic impact on the production line.
To address these issues, Feature-Tec has conducted research and developed a tantalum heat exchanger as a replacement for graphite heat exchangers. This program aims to solve the problems of silica mud deposition scaling and the frequent and cumbersome maintenance required.
Product Advantage:
Tantalum possesses excellent properties such as corrosion resistance, toughness, ductility, thermal conductivity, and a high melting point. It can be used as a replacement for stainless steel in various inorganic acid production equipment and waste acid concentration equipment, offering a lifespan dozens of times higher than stainless steel. Tantalum also exhibits exceptional chemical properties, displaying very high corrosion resistance. It remains unreactive to hydrochloric acid, concentrated nitric acid, and "aqua regia" under both cold and hot conditions. Immersion in sulfuric acid at 200°C for a year only results in a surface layer damage of 0.006 mm. Experimental results have demonstrated tantalum's excellent corrosion resistance, similar to glass, except for hydrofluoric acid, fluorine, fuming sulfuric acid, and alkali. These unique properties of tantalum have greatly expanded its application possibilities.
The presence of a 1mm fouling layer in a heat exchanger reduces the heat transfer coefficient by approximately 10%. Therefore, reducing fouling in heat exchangers is a critical factor for achieving long-term stable operation. Tantalum's metallic properties significantly increase the acid flow rate, allowing for high-speed scouring of the tantalum tube's surface. Additionally, the inner surface of the tantalum tube is exceptionally smooth, preventing the accumulation of silica mud and ensuring efficient and stable heat exchanger operation. Compared to graphite heat exchangers, tantalum heat exchangers feature an all-welded structure, providing overall stability and eliminating uncertainties caused by graphite brittleness during lifting and installation. Furthermore, during the cleaning process, tantalum heat exchangers do not exhibit erosion defects similar to graphite under high-pressure scouring.