Matters needing attention in the operation of graphite heat exchanger

Precautions for graphite heat exchangers: Over-temperature and over-pressure operations are prohibited during use, and sudden changes in temperature and pressure should be avoided. All valves should be opened slowly, and gradually adjusted to the maximum or minimum, avoid the violent impact of the steam when the steam is heated, and slowly heat up when the equipment is in operation. pressure, the operation of the preheating process is very important. Operation process: The cold carrier (material medium) should be passed through first, and then the heat medium (steam or hot water) should be passed after the equipment is full; Stop the cooling carrier (material medium) from time to time to check the acidity and alkalinity of the condensed water, regularly analyze the material composition of the tube side and the shell side, and check whether cross leakage occurs.

Clean up the debris in the process pipeline before starting the graphite heat exchanger to prevent the graphite pores from being blocked. Minimize the number of times the equipment is driven and parked as much as possible to extend the service life of the equipment. When the heat transfer of the equipment can be lowered, it should be parked to check. If the equipment is seriously fouled, it can be cleaned by appropriate physical or chemical methods; if the tube is blocked by crystals, it can be heated and melted for cleaning. Because graphite is a brittle material, mechanical methods are prohibited. The highest (lowest) part of the shell is provided with an exhaust (net) pipe. When installing, a valve should be installed, and then connected to the exhaust (net) pipe. It is forbidden to blindly die with a blind plate. Before the initial use of the equipment, the emptying valve on the top of the shell should be opened and closed after the air in the shell is completely swept away. During use, it is necessary to discharge the non-condensable gas at the top of the shell side and the condensed water at the bottom frequently.

The larger the particle size of the graphite base material, the smaller the material bulk density and the lower the mechanical strength. The larger the pores between the particles, the more through-holes may be exposed when the holes are drilled, and the porosity increases. In order to achieve the compactness required by the application, the amount of impregnant will increase, affecting the impregnation quality and the thermal conductivity of the impermeable graphite. The higher the density, the higher the mechanical strength. Therefore, the use of base materials with high bulk density (fine particles, B-grade) for processing and production equipment after immersion heat treatment has high quality stability and safety, and good performance. The graphite heat exchanger impregnating agent fills the open space in the graphite base material. Different types of impregnating agents will directly affect the corrosion resistance of impermeable graphite. Different immersion amount will affect the operating temperature and corrosion resistance level of impermeable graphite. The impregnation vacuum degree is large, the pressurization pressure is high, the number of impregnations can be reduced, and the heat exchange effect is also better than the traditional impregnation process (three times of impregnation and three times of heat treatment).