Everyone, let’s discuss how to purge the pipelines
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The thickest of these pipes is 54 inches, while the thinnest is 42 inches, but the design is confusing. The 54-inch end does not have a flange; it will be welded directly to another device. This end is connected to two heat exchangers. Blind plates can be installed at the heat exchanger locations, and access holes for cleaning are provided, but even when entering through these holes, it is impossible to clean the area due to the numerous bends. I was thinking that a blind flange should be welded on that end, and the heat exchanger end should also be sealed with a blind flange; then, blasting could be carried out through the manholes in both pipes. I’m not sure if this method will work. By the way, the pressure in these pipes is -50, with a design pressure of 2.7 kilograms.
The design pressure ranges from -50 to 2.7 kilograms; therefore, blasting for cleaning falls within this range. The volume of gas used in this process is not large, so the cleaning effect will be limited. It can be tried, but one shouldn’t have high expectations. Ultimately, it is still necessary to use materials to remove impurities and dust from inside the pipes
The design pressure ranges from -50 to 2.7 kilograms; therefore, blasting for cleaning falls within this range. The volume of gas used in this process is not large, so the cleaning effect will be limited. It can be tried, but one shouldn’t have high expectations. Ultimately, it is still necessary to use materials to remove impurities and dust from inside the pipes
The material brings dirt into the heat exchanger; it’s a coil-type heat exchanger, so it’s not easy to clean
So, try to use devices connected to the pipelines, such as storage tanks, as containers for storing gas; this way, in the event of an explosion, there will be more gas available for evacuation. Relying solely on the volume of the pipelines does not provide much gas
That’s exactly the difficulty: these pipes connect two heat exchangers, and although access holes for cleaning have been designed, there are still several bends. I’m stuck here while trying to write the plan :(
This post was last edited by CHANGBAISHI on 2021-2-1 08:41. Blowing holes should be installed before connecting these devices. If necessary, special purging holes should also be provided. The key issue is the recovery work after purging; no impurities must be generated, and that is what needs to be done. For reference.
Your drawing really isn’t that good; it’s hard to understand.
This post was last edited by chen/74 on 2021-2-2 at 13:24. Install a double-check valve; blow from the direction of the heat exchanger, and after purging, clean it out through the cleaning port up to the elbow in the upward section. From a cost perspective, a self-stopping device can be used. If the pipe diameter is too large, blasting is not a suitable method for cleaning it.
For such a large pipeline, wouldn’t it be better to use a manhole to clean it with a high-pressure water gun? For smaller pipes, steam or nitrogen blasting is a good option. Your 54-inch pipeline is considered a large-scale equipment – what diameter steam pipe should be used? For blasting, the steam flow rate must be no less than 25 m/s; calculate how much steam is required yourself
In this case, the pipeline should be purged first, and then the weld joint of the heat exchanger should be welded to create a high-quality weld.