Issues with adding metal linings to pressure vessels in use
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One of the company’s currently in-use pressure vessels has severe corrosion in its tower bottom; it is planned to apply a metal lining to this area. However, the local pressure vessel inspection agency does not approve of this approach, as there are no precedents for it. I would like to ask those with experience whether this method is feasible Are there any precedents to follow? Is it in compliance with the standards?
It is very difficult to ensure the quality of the internal metal lining; if not handled properly, the medium can penetrate through the seams in the lining and enter the interlayer, causing severe localized corrosion and increasing the risk of catastrophic accidents.
One is not allowed to make repairs on their own; all repairs are incorporated into the design at the initial stage of container design.
In fact, a non-metallic lining can also be considered
In fact, there’s no need for you to consult the special inspection agencies. The local special inspection agencies have only a few experts; they are nothing but fake bureaucrats from public institutions. A handful of expert-level individuals can be found in a few institutions, and they are the ones who maintain the appearance of legitimacy for the entire industry. What you should do is to entrust a qualified, capable, and experienced design institute to develop plans and design documents; construction should then be carried out in accordance with those designs, and the special inspection agency should also conduct supervision and inspections based on the design documents! (Regarding compliance with regulatory standards, designers will think more thoroughly and professionally.) Even if it’s your own proposal, it must be transformed into a formal design by the design department before it can be implemented. Regarding the solution, adding a metal lining inside the existing pressure vessel is not very practical, so it should be used with caution. The most effective approach is to take technical measures to eliminate the corrosive environment; if this cannot be achieved, it is a problem of improper material selection during the initial design, and it should be updated.
Adding a metal lining requires redesign; calculations based on standards show it meets the requirements. Adding a lining cannot be done casually; many factors need to be taken into consideration
A qualified entity is required to carry out the design and calculations, and to produce the drawings. In the situation described by the original poster, the ideal solution is to replace it; otherwise, the degree of thinning needs to be considered – if it’s only a few millimeters, cladding could be an option. Even for surfacing, a qualified design firm is required to prepare a repair plan. The metal lining is considered at the start of equipment manufacturing; thinning it after in-use inspection is not allowed here, as our inspection facility does not permit the use of linings.
The simplest solution is to apply a 3–6 mm thick corrosion-resistant coating; however, this is quite expensive and requires manual handling