Precautions for the use of graphite heat exchanger: It is strictly prohibited to operate over temperature and over pressure, and block hole graphite heat exchanger shall be prevented from sudden changes in temperature and pressure. All valves of anti-corrosion equipment shall be slowly opened and gradually adjusted to Z large or Z small. During steam heating, severe impact of steam shall be prevented. During equipment operation, the temperature shall be slowly raised. When the temperature of graphite parts tends to be average, the pressure shall be slowly increased until the normal operating pressure is reached. The preheating process is very important. Operation steps: cold carrier (material medium) shall be connected first, and then heat carrier (steam or hot water) shall be connected after the equipment is filled; During shutdown, the heat carrier (steam or hot water) shall be stopped first, and then the cooling carrier (material medium) shall be stopped after the equipment cools down to check the acid and alkali of condensate irregularly, analyze the material composition of tube side and shell side regularly, and verify whether the leakage can occur.
The impurities in the process pipeline shall be cleared before the start-up of the graphite heat exchanger to prevent blockage of the graphite channel. Reduce the number of equipment startup and shutdown as much as possible to extend the service life of the equipment. When the heat transfer of the equipment can be reduced, it shall be stopped for inspection. If the equipment is severely scaled, appropriate physical or chemical methods can be used for cleaning; If the tube is blocked by crystals, it can be heated, melted and cleaned. Since the graphite is brittle, it is strictly prohibited to use mechanical methods to dispose of it. The high (low) Z part of the shell is provided with an exhaust (net) pipe, which shall be connected to the exhaust (net) pipe after being equipped with a valve. It is strictly prohibited to blind it with a blind plate. Before the equipment is put into operation, the vent valve at the top of the shell shall be turned over and closed after the air inside the shell is completely removed. The non condensable gas at the top of the shell side and the condensate at the bottom must be regularly discharged during the operation.
The larger the particle size of the graphite base material is, the smaller the volume density of the data is and the lower the mechanical strength is. The larger the holes between particles, the more through holes may be exposed during drilling, and the porosity will increase. In order to achieve the required compactness, the amount of impregnant will increase, affecting the impregnation quality and the thermal conductivity of impermeable graphite. The higher the density, the greater the mechanical strength. Therefore, the equipment with high bulk density (fine particles, Grade B) for processing and consumption after stop impregnation heat treatment has high quality stability and safety, and good application effect. The impregnant of graphite heat exchanger fills the voids in the graphite base material. The different types of impregnant will directly affect the corrosion resistance of impermeable graphite. The application temperature and corrosion resistance of impermeable graphite are affected by different immersion amount. The large vacuum degree and high pressure of impregnation can reduce the number of times of impregnation, and the heat transfer effect is also superior to the traditional impregnation process (three times of impregnation and three times of heat treatment).
