Problems with heat exchangers
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A heat exchanger that has been in use for one year experienced leakage of the fluid in the tube side to the shell side. Shell side material: Q345R, heat exchange tubes: S30408, tube sheet: 16MnⅢ+S30408. The heat exchange tubes and tube sheet are joined using strength welding plus expansion bonding. The parameters are as follows: https://attach01.hcbbs.com/forum/202001/12/090303fwza7tbcdcpa9kd4.png. The piping schematic is available at https://attach01.hcbbs.com/forum/202001/12/091013um5ndpwfwqwj50fj.png. The baffle plates have broken: https://attach01.hcbbs.com/forum/202001/12/090700l5noqwvukv5v35nz.jpg. Several heat exchange tubes at the connection point between the heat exchange tubes and the tube sheet have broken; however, the weld joints between these tubes and the tube sheet are intact: https://attach01.hcbbs.com/forum/202001/12/090552ynndy04q4kc7kcc4.png. The connections in the shell side have suffered severe corrosion: https://attach01.hcbbs.com/forum/202001/12/090646ieescow66mwqbohz.jpg. Friends, please analyze the reasons. Thank you.
The material, installation, operation, and other factors can all lead to this phenomenon.
It seems to be caused by the vibration of the tubes
Whether the manufacturing of the baffle tube holes meets the standard deviation requirements, and whether the baffle tube holes have chamfers or rounded edges.
What gas does the shell layer carry? Here, we use shifted gas, and tube corrosion occurs.
It is likely that inappropriate operating parameters or issues with the design structure are causing vibration in the heat exchange tubes
This post was last edited by bluishice on 2020-1-13 at 15:26. Since the fluid is leaking from the tube side to the shell side and the tube ends are intact, it must be the heat exchange tubes that are leaking. There are only a few reasons for leakage in the heat exchange tubes: 1. Severe pitting occurs inside the tubes. 2. The heat exchange tubes are defective and have leakage points. 3. Excessive pulling force causes stress corrosion. 4. Tube bundle vibration.
The tube side medium leaks into the shell side, causing hydrogen sulfide corrosion of the carbon steel in the shell side.
At the air intake, it’s probably caused by washing
The baffle is made of carbon steel and serves to support the tube bundle, which is made of 304 material; this indicates that the medium flowing in the shell side is corrosive. When the baffle corrodes, the tube bundle loses its support, starts to vibrate, and breaks under the stress applied at the points of failure.