The operation cycle of the heat exchanger should be consistent with the production cycle of the production device. In order to ensure the normal operation of the heat exchange equipment and meet the requirements of the production device, in addition to regular inspection and supervision, daily maintenance and repair are also indispensable.
We should take special care to prevent fluctuations in temperature and pressure in daily operations. First, the pressure should be stable, and never allow overpressure operation.
Leakage problems are most likely to occur when starting and stopping line sweeping. If the floating head of the heat exchanger is prone to leaks, we should open the outer closure head of the floating head first to check the pressure test from the pipe side when repairing. Sometimes the floating head bolts are not tight. This is due to the plastic deformation caused by long-term heating of the bolt.We usually take the measures to test the pressure with steam after the tube bundle hydraulic pressure test gets through.
When the temperature rises to 150~170℃, the bolts can be tightened again, so that the floating head has better sealing.Most of the heat exchanger failures are caused by the tubes. The perforation of the tubes due to corrosion should be replaced in time. If only the individual tubes are damaged and it is more difficult to replace, the ends of the bad tubes can be blocked with pipe plugs. The hardness of the pipe plug material should not exceed that of the pipe material, and the total number of blocked pipes should not exceed 10% of that of pipes in the pipe pass. We should clean heat exchangers that are prone to scaling in time to avoid affecting the heat transfer efficiency.
1. During the steam purging of the installation system, we should avoid the purging of the coated cold exchange equipment as much as possible. When we decide the process to be unavoidable, we should strictly control the purge temperature at no more than 200 degrees Celsius to avoid damage to the coating.
2. During the start and stop of the device, we should slowly heat and cool the heat exchanger to avoid excessive pressure difference and thermal shock. At the same time, it should follow the “heat first and then cool” during the shutdown, that is, first removing the heat medium and then the cold medium; “Cold first, then hot” when starting work, that is, receiving cold medium, then heat medium.
3. Before starting work, make sure that the threaded locking ring heat exchanger system is smooth and avoid over-pressure on one side of the tube sheet.
4. Check the operating parameters of the heat exchange equipment carefully, and prohibit over-temperature and over-pressure. For heat exchangers designed with differential pressure, it shall not exceed the specified differential pressure during operation.
5. The operator should strictly abide by the safety operation regulations, conducting regular patrol inspections on the heat exchange equipment, checking the foundation support for stability and equipment leakage, etc.
6. We should check frequently the temperature and pressure drop of the medium in the pipe and the tube pass to analyze the leakage and scaling of the heat exchanger. When the pressure drop increases and the heat transfer coefficient decreases beyond a certain value, we should select an effective method for cleaning according to the structure of the medium and the heat exchanger.
7. We should check the vibration of the heat exchanger frequently.
8. During operation, we should strictly control the temperature of cold-swappable equipment with anti-corrosion coating to avoid coating damage.