Discussion on the issues with this tubular device
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As the title suggests, I’m facing a problem at work: a tubular device with DN800； L=100m ； Installed on a duct bank at a height of around 15m ； The working medium is gas, and the device is subject to pressure fatigue conditions with pressures ranging from 0 to 3.0 MPa. During the design phase, the tank engineering department was tasked with carrying out fatigue calculations and designs; however, it seems inappropriate to classify this equipment as a pressure vessel ； As a pressure pipeline, there is ambiguity due to the existence of separate manufacturing drawings (which include the manufacturing and inspection standards for various pressure vessels). I would like to ask everyone how this equipment can be classified in a more scientific and reasonable manner? There are great prizes for those who participate!
According to GB 150, it is still considered a pressure pipeline, or at most it can be regarded as a pipe fitting used in equipment
I also hope for a more detailed explanation; thank you!
If it is simply a long section of pipe whose main purpose is to transport a medium, it should be classified under pipes in the appropriate category
Tubular reactors, fixed-bed reactors, and fluidized-bed reactors all fall under the category of reactors~~~~ They should be covered by the requirements of TSG21. However, point 1.4.1(3) mentions “ultra-high-pressure tubular reactors”; yet in section 1.5, there is no mention of “tubular reactors with high pressure, medium pressure, or a working pressure lower than medium pressure”~~~~ This is not precise enough~~~~ @Original poster, since there are manufacturing blueprints, check if there is a classification indicated in the upper right corner of those blueprints~~~~ It should at least be classified as Category II, and supervision during manufacturing is required by the special inspection agency~~~
“”But it seems inappropriate to classify this device as a pressure vessel. What is the basis for this inappropriateness? Is it because of the length-to-diameter ratio? Firstly, it is necessary to follow the nature and content of the design documents [design basis, classification, various manufacturing parameters/requirements, various testing requirements]. Secondly, it is important to understand the main function of the equipment/pipeline. For example, in a tubular catalytic cracking unit, the lift pipe has a relatively large length-to-diameter ratio; its primary function is to serve as a place where the feedstock and catalyst are mixed and reacted. Therefore, it functions as a reactor, that is, it is equipment.