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To ensure the long-term proper operation of heat exchangers, it is necessary to operate and use them correctly, as well as pay attention to the maintenance, upkeep, and inspection of the equipment. Preventive maintenance should be given top priority, with an emphasis on safety measures to reduce any potential accidents. This requires us to master the basic operating methods, operational characteristics, and maintenance practices related to heat exchangers. On this issue, I hope everyone will share their views. When the heat exchanger is cooled by circulating water, attention must be paid to corrosion and scaling prevention, otherwise the tubes of the equipment may get damaged. If the heat exchanger is heated with steam, care must be taken to prevent water hammer, as it can cause severe damage to the equipment! ! The heat exchanger should be opened regularly to check the condition inside it; if any problems are detected, the equipment must be repaired promptly! ! ! Different types of heat exchangers require different approaches in terms of use and maintenance. For shell-and-tube heat exchangers, special attention must be paid to leaks in the shell during routine maintenance. Fixed-plate heat exchangers cannot be used in environments with large temperature fluctuations; in such cases, the percentage of leakage in the tube side should not exceed 10% of the total tube length, otherwise the heat exchanger must be replaced. Plate-type heat exchangers are a type of large-scale heat exchanger required in large chemical and petroleum refining plants. But it is quite delicate. It is also used with great care. Firstly, the tube bundle of a plate heat exchanger can only withstand a pressure difference in one direction; that is, the pressure on the cold side must be higher than that on the hot side, with the pressure difference being less than 0.35 MPa. Secondly, the temperature difference at the hot end must not exceed 50 degrees. Thirdly, the heating rate must not exceed 50 degrees per hour. Fourth, the coexistence of chlorides and liquid water should generally be avoided, as the tube bundles are made of stainless steel and will corrode if exposed to an environment of chlorides + water for an extended period. Fifth, the tube bundle of a plate heat exchanger cannot withstand internal pressure; if the pressure at the feed and outlet is greater than the pressure at the inlet of the circulating gas, the tube bundle will be damaged. I. Driving operations and precautions 1. When using it on new process pipelines, be sure to remove any debris from within the pipelines to prevent clogging of the heat exchangers. 2. If wastewater is used as the cooling medium, or if the waste heat from the wastewater is to be recovered, or if the medium contains particulate solids, a filter or dirt remover should be installed at the inlet of the heat exchanger to prevent it from getting clogged. 3. When the temperature of the cooling water (after being heated) exceeds 40°C, softening treatment should be carried out as much as possible to prevent scaling in the heat exchanger, which could affect heat transfer efficiency. 4. Check whether the pipeline connections are correct to prevent the mixing of the two media, which could lead to adverse consequences. 5. Before starting the machine, carefully check whether the inlet valves for the cold and hot media are closed and whether the outlet valves are open. 6. The device can be turned on only after the above tasks are completed. When starting the vehicle, first activate the pumps for the cold and hot media. Slowly open the inlet valve for the cold medium, and then open the inlet valve for the hot medium, allowing the media to flow into the heat exchanger gradually to prevent excessive temperatures. 7. Check all sealing surfaces and all welds for any abnormal conditions such as leaks. 8. Raise the temperature slowly, while simultaneously measuring and calculating whether the process requirements are met. Once these conditions are met, normal operation can proceed. If the plate heat exchanger starts operating properly, but after running for a while it begins to deviate from the specified process requirements, such as an increase or decrease in pressure drop ； The medium outlet temperature rises or falls. The method to handle this fault is: A. Check whether the inlet parameters of the cold and hot media match the original design values. If it does not match, efforts should be made to adjust it back to the original value. If the inlet parameters have changed and it is not possible to adjust them to the original design values, then redesign calculations must be carried out to determine whether to increase or decrease the heat exchange area or to modify the process configuration. B. If the inlet parameters of the cold and hot media match the original design values, but the outlet parameters do not meet the design values, the system should be shut down; the plates should be removed to check for any blockages or scaling, and such issues should be addressed promptly. There are many types of heat exchangers, including those for gas-to-gas heat exchange, gas-to-liquid heat exchange, and liquid-to-liquid heat exchange. They can operate at low pressures or high pressures; there are also regenerative heat exchangers as well as those designed to handle corrosive media – the variety is truly extensive! In fact, a boiler is also a type of special heat exchanger, and the operating requirements for each type of heat exchanger vary; in some cases, they differ greatly! This topic is quite extensive! Key points for using plate-fin heat exchangers: 1. Since they are primarily used at low temperatures, it is best to reduce the temperature at a rate of 3 degrees per minute during startup; the cooling rate should not be too fast, to avoid local stress-induced damage to the plates. 2. As it is a compact heat exchanger with a small temperature difference, the flow channels within it are very narrow; the high-density fins used inside must prevent blockages by foreign objects. This type of heat exchanger is used inside the low-temperature cryogenic chambers in the petrochemical industry; it is advisable to install filters at the inlet of the channels to prevent the entry of sand particles and welding residues left over from pipeline construction. 3. It cannot be used in environments with corrosive substances that affect aluminum, as this will reduce the service life of the heat exchanger. To prevent mercury in natural gas processing from causing corrosion to aluminum, a form of damage that is common in LNG and light hydrocarbon processing plants. 4. During the pressure testing of the equipment pipelines, it is advisable to install the heat exchanger only after all other equipment and pipelines have been tested. This is because such heat exchangers are sealed with N2 before leaving the factory, in order to prevent dirty gases and water from entering them; water and CO2 can freeze at low temperatures and damage the heat exchanger. Here is a brief summary; I hope it will be of some help to everyone.