Pressure vessel maintenance
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There is a leak at the weld between the cylinder lining and the pipe lining at the outlet connection for the reaction gas on the shell side of the methanol water cooler (N2). Are there any good repair methods? 1. It’s not possible to access the pipe end with a DN450 diameter. 2. If the material of the connection pipe is changed, can it be carried out in accordance with the standards of the original drawings?
Rectify in accordance with the modification plan! Obtain the consent of the design unit!
Replacing the tube bundle in a fixed-tube-sheet heat exchanger is essentially equivalent to replacing the entire heat exchanger.
This post was last edited by chenjdvip on 2022-4-4 09:43. Find a short welder to go in and perform patch welding.
Is there a robot that can weld in this situation?
In your case, it seems that there is a leakage in the corrosion-resistant layer inside the weld between the shell tube (composite plate) and the nozzles (N2 16Mn with 321 surfacing). If it’s only the corrosion-resistant layer that’s corroded, it’s sufficient to have a welder with limited skill perform repairs using 321 welding material (the corrosion-resistant layer does not contribute to the structural strength). We have previously carried out repairs on the inside of 400-series pipes, and the amount of welding required was relatively small. If both the internal corrosion-resistant layer and the external base layer have been corroded through, you need to determine the area of the corroded portion. Depending on whether the area of corrosion is large or small, decide for yourself whether to carry out patch welding or opt for a replacement solution.
For core extraction and tube replacement, there are specialized devices that make the process quick.
DN450 can be repaired; in actual production, those with an inner diameter greater than 380 can also be repaired. Compressed air is introduced into the reinforcement ring; soap water is used to detect leaks, followed by grinding and repair. Avoid entry due to safety or other factors; compress air from the outside, use mirrors to detect leaks inside, wear through the outer side of the affected area, and repair it from the outside