Precautions for graphite heat exchanger

2020-12-16261

        It reminds the attention of graphite heat exchanger that the operation of over temperature and pressure is strictly prohibited, and sudden change of temperature and pressure should be prevented. All valves shall be opened slowly and adjusted to large or small gradually. The steam shall be heated to prevent the violent impact of steam. During equipment operation, the temperature shall be raised slowly. When the temperature of graphite parts tends to average, the pressure shall be increased slowly until it reaches the normal operating pressure. The operation of preheating process is very important. Operation steps: the cooling carrier (material medium) shall be opened first, and then the heat carrier (steam or hot water) shall be supplied after the equipment is filled; the heat carrier (steam or hot water) shall be shut down when the equipment is shut down, and the cold carrier (material medium) shall be shut down after the equipment is cooled. The acid and alkali of the condensate water shall be checked irregularly, and the material composition of the tube side and shell side shall be analyzed regularly to determine whether the string leakage can occur.

        Before the start-up of the graphite heat exchanger, the impurities in the process pipeline should be cleared to prevent the graphite channel from being blocked. Reduce the number of startup and shutdown of the equipment as much as possible to extend the service life of the equipment. When the heat transfer of the equipment can be reduced, it should be stopped for inspection. If the equipment has serious scaling, it can be cleaned by appropriate physical or chemical methods; if the pipe is blocked by crystal, it can be cleaned by heating and melting; because graphite is brittle material, mechanical treatment is strictly prohibited. When the high (low) part of the shell is equipped with an exhaust (clean) pipe device, the valve shall be installed, and then the exhaust (clean) pipe shall be connected. The blind plate shall be strictly prohibited. Before the equipment is put into operation, the vent valve I] on the top of the shell shall be opened and closed after the air inside the shell is completely swept away. In the process of operation, the non condensable gas at the top of shell side and the condensate water at the bottom should be discharged frequently.

        The larger the particle size of the graphite base material, the smaller the volume density of the data and the lower the mechanical strength. The larger the hole between particles, more through holes may be exposed and the porosity will increase. In order to achieve the required compactness, the number of impregnating agents will increase, affecting the thermal conductivity of the impregnation and impermeable graphite. The higher the density, the greater the mechanical strength. Therefore, the equipment with high bulk density (fine particles, grade B) is selected to stop impregnation heat treatment, and the equipment for processing consumption has high quality stability and safety, and the application effect is good. Different kinds of impregnating agents will directly affect the corrosion resistance of impermeable graphite. Different immersion amount will affect the application temperature and corrosion resistance level of impermeable graphite. The results show that the impregnation vacuum is large and the pressure is high, which can reduce the times of impregnation, and the heat transfer effect is better than the traditional impregnation process (three times of impregnation and three times of heat treatment).