The tube boxes and shell at both ends of the shell-and-tube heat exchanger are welded together
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I once saw a heat exchanger with a diameter of 4 meters, whose tube boxes at both ends were welded to the shell, rather than being connected by flanges. During each major overhaul, personnel can be sent in to inspect the pipes. I recently saw another such heat exchanger, but its diameter is only 400 mm. Why is it designed this way? Personally, I think this makes it difficult to inspect the heat exchange tubes in the future; a flange connection would be better. The shell side contains oil, while the tube side contains ammonia gas.
For heat exchangers with a diameter of 4 meters, it is difficult to achieve a leak-free seal using flange connections. Flange connections with a diameter of 400 mm can be easily sealed.
For some reason, a pipe once leaked; the only solution was to cut both ends of it, seal the pipe, and then weld the pipe ends back to the pipe boxes. Carbon steel equipment exposed to ammonia can easily suffer from stress corrosion cracking, especially when heat treatment is not carried out after welding, or when the heat treatment is inadequate.
Once accustomed to a certain format, one is reluctant to change it, right?
No innovation means certain failure:D
No innovation means certain failure:D
Standard shell-and-tube heat exchangers should be flanged, with only very large ones being welded.
The shell-and-tube heat exchangers in the process pipelines of our equipment are all welded, monolithic units
The shell-and-tube heat exchangers in the process pipelines of our equipment are all welded, monolithic units
Are there any special considerations in terms of manufacturing processes or anything else? If the diameter of the heat exchanger is small, it’s difficult to inspect the heat exchange tubes.
Is there a reference standard, or is it based on experience?