Thread Content
Advantages of tetrafluorine heat exchangers: (1) Extremely high corrosion resistance: They have stable chemical properties, are inert to almost all chemicals and solvents, and hardly any solvent or compound can dissolve them at temperatures below 300°C; thus they can be used in most harsh working environments. (2) Resistance to high and low temperatures: Non-metallic materials do not become brittle at low temperatures ranging from -190°C to 260°C, nor do they soften at high temperatures, allowing them to be used normally. (3) Superior dust removal capability: It has the lowest surface tension among solid materials, with a very large surface contact angle, and does not adhere to any substances ； The pipe wall has a smooth surface and moderate flexibility; it vibrates slightly during use, which makes scaling less likely to occur ； Installing a dust cleaning device at the same time effectively solves the problem of dust accumulation. (4) Excellent wear resistance: Non-metallic materials possess excellent wear resistance, and by selecting smoke flow velocities that result in low wear and low resistance, the wear on the tubes of the PTFE heat exchanger is reduced. (5) Long service life: Non-metallic materials contain no photosensitive components, making them highly resistant to aging. They have a similar aging resistance to plastics, and are also strong against wear; they are not prone to clogging with dust. Under normal conditions, non-metallic heat exchangers can be used for 10–15 years. (6) The costs are reasonable. Although fluoroplastic, used as a heat transfer element, is still expensive at present, the use of small-diameter thin-walled tubes can result in an overall heat transfer coefficient of up to 500 W/㎡·℃. When such heat exchangers are produced in bulk under well-developed manufacturing processes, their excellent corrosion resistance allows them to replace rare metals, thereby saving a significant amount of these valuable materials. Furthermore, due to the advantages of fluoroplastic heat exchangers such as corrosion resistance and dirt resistance, other economic benefits can be obtained during their use. Therefore, taking into account factors such as manufacturing, installation, operation, and maintenance, the actual cost is relatively low. It is these advantages that enable PTFE heat exchangers to be used more widely: 1. PTFE heat exchangers as hydrofluoric acid heaters – There are significant challenges in selecting equipment for heating hydrofluoric acid. Due to its high permeability, non-metallic materials can be used; graphite-based equipment works, but its lifespan is short because this medium can easily penetrate such materials. Glass equipment is also unsuitable as it cannot withstand the corrosion caused by hydrofluoric acid. Some manufacturers use PTFE heat exchangers as hydrofluoric acid heaters, with the heating medium flowing inside the heat exchange tubes while the exterior of the tubes is lined with PTFE. This allows liquid hydrofluoric acid to be heated to gaseous hydrogen fluoride. The system is connected to pipes and the ambient pressure, thereby solving the problem of difficult long-term use of rare metal equipment. Below is a picture of this type of equipment. 2. PTFE heat exchangers for nitric acid heating – Heating nitric acid of moderate concentration to temperatures above 120°C has always been a challenging task. Graphite heat exchangers were previously used, but they would get damaged after about a month due to the strong oxidizing properties of nitric acid. Thanks to our optimizations of PTFE heat exchanger design and years of research, we have successfully overcome this issue. Using steam or heat transfer oil for heating nitric acid can meet the required standards, thus helping manufacturers resolve their urgent needs.