Is there any leakage at the flange of the wall valve on the catalyst regenerator unloading line? How to control
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The descaling line is used intermittently; it has been in use for two years. Recently, there has been slight leakage at the flanges on the vessel walls. Has anyone encountered the same problem? Is it caused by uneven heating? Are there any measures that can be taken to control this?
It’s possible that the catalyst has worn through the flange; valve installations on the vessel walls are rather troublesome. Using a time tracker is one way.
The gasket cannot be replaced on the vessel wall flange; if catalyst leaks out, the issue will spread rapidly, so it is necessary to call maintenance personnel immediately to weld the entire area shut.
Due to the shutdown and catalyst unloading, the bottom flange of the regenerator may experience bolt loosening, resulting in slight leakage. However, this does not affect the catalyst unloading process. This situation occurs quite frequently and isn’t a major issue
If there’s enough space, just put on a clip; if not, weld a box. The fittings on the dosing and de-dosing pipelines in intermittent operation should not present any problems.
During the major overhaul, we pre-made boxes at the pipeline and valve flanges; the welds of these boxes cracked, but leakage stopped when the fluid discharge was halted. The cracked areas were then repaired and strengthened by welding. However, with the major overhaul still a year and a half away, there is still a risk of leaks.
Close the blowback valve of the leakage valve box, and pre-install a valve on the agent discharge line located near the leakage valve. With the leak valve fully open, a slight amount of backflow air is used to maintain pressure in the box. In the future, the agent removal will be controlled by a pre-made valve.
If wear occurs, thickness measurement must be carried out first; welding repairs should not be done blindly, as welding on an excessively thin surface can cause damage. Let’s switch to another discharge port first. Normally, control the desizing speed and temperature. There is also the option of modifying it for external heat removal and catalyst unloading.
The thermal catalyst will leak more and more severely.
There are no specific values; just keep the temperature at around 450.