Metal-impregnated graphite is called impregnated graphite, and impregnated graphite is also called plastic-impregnated graphite or impregnated impermeable graphite. The graphite is impregnated with synthetic resin to fill its surface and internal pores, and then heat-treated to cure the resin.
What are the properties of metal impregnated graphite? The performance is as follows:
- Excellent corrosion resistance:
The maximum application temperature is 350℃-400℃, that is, the temperature at which carbon and graphite begin to oxidize.
- Excellent thermal conductivity
In addition, graphite also has good thermal conductivity, which is the highest thermal conductivity of non-metallic materials than metals. The thermal conductivity is 2 times that of carbon steel and 7 times that of stainless steel. Therefore, it is suitable for use in heat transfer equipment.
- The surface is not easy to structure:
The “affinity” between graphite and most media is very small, so dirt is not easy to adhere to the surface. Especially used in condensation equipment and crystallization equipment.
The use temperature of impermeable graphite depends on the type of impregnating material. For example, phenolic impregnated graphite can withstand 170-200 ° C. If an appropriate amount of silicone resin is added to impregnate graphite, it can withstand up to 350 ° C; when phosphoric acid is deposited on carbon and graphite , the actual operating temperature can be further increased.
The lubricity of graphite is similar to that of molybdenum disulfide and tetraethylene. The friction coefficient is less than 0.1 in the lubricating medium. The lubricity of graphite varies with the size of the flakes. The larger the flakes, the smaller the friction coefficient, and can be pressed into any complex shape. Graphite products, graphite heat exchangers, graphite absorbers, graphite evaporators and other equipment made of graphite can be used in gases, vapors, liquids, ductile substances or crystalline substances.
The shell-and-tube graphite heat exchanger is a floating head type, the upper tube sheet (fixed tube sheet) and the lower tube, the plate (sliding tube sheet) are mostly made of 400mm thick impregnated graphite, which has good machining performance. Low density, light weight, paste a layer of 50mm thick high-strength fiberboard or other anti-corrosion materials on the sliding tube plate, suitable for non-oxidizing or weakly oxidizing strong acids, alkalis, salt solutions, most organic solvents and composite organic acids medium, suitable for making various heat exchange equipment.
The graphite anti-corrosion falling film evaporator adopts steam heating and evaporation, and the parts of the equipment in contact with the corrosive medium are made of impregnated graphite. Good chemical stability, high evaporation efficiency, low energy consumption, high temperature and pressure resistance, easy maintenance, long service life, can be widely used as anti-corrosion workplaces, mainly used for evaporation, concentration of corrosive materials, divided into columns For tubular graphite falling film evaporator and round block hole graphite falling film evaporator, it is recommended to use the round block hole graphite evaporator with better performance.