There are multiple leakage points in the waste heat boiler; I’m not sure of the cause and seeking help.
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The situation is as follows: it is a waste heat boiler, with the boiler feed water pipeline operating at a temperature of 150°C and a pressure of 6.6 MPa. Both the valve flanges and the pipeline flanges are of the raised-face type. After the boiler had been in operation for about 10 days, numerous leakage points appeared at the valve connections. All of the pipelines where leaks occurred were those connected to the boiler as part of the boiler feed water system; there were no leaks in the medium-pressure steam pipelines. What could be the possible causes of these leaks?
6.6 MPa – that’s quite a high pressure
Isn’t it true that heat sealing isn’t necessary unless the temperature is below 250 degrees? Moreover, there’s a strange issue: after running for about ten days, many leakage points appeared suddenly, and some of these leakage points disappeared on their own the next day
Isn’t it true that heat sealing isn’t necessary unless the temperature is below 250 degrees? Moreover, there’s a strange issue: after running for about ten days, many leakage points appeared suddenly, and some of these leakage points disappeared on their own the next day
The pressure is quite high; could it be that the excessive pressure is the result of not using flanges with a ribbed surface?
You have chosen the wrong type of flange; WN RJ should be used instead. Also, is the choice of fasteners correct? 25cr2mov should be used
What material is your pipe made of, and can it withstand this pressure?
Are you sure a raised-face flange can be used for a pressure of 6.6 MPa? At least concave-convex surfaces should be used, or even tenon-mortise surfaces; the choice can be made based on the pressure-temperature chart in HG20592. Including gaskets.
We have encountered such problems in fuel gas pipelines. There’s a problem with the flange surface of ours. Also, the flanges are not parallel during welding.
At a pressure of 6.6 MPa, flanges with uneven surfaces and tenons are necessary; how can you really be confident about that?； Has the pipeline connection been welded? For the valves in the boiler systems we supply, those rated at 4MPa use male and female faces, with the flange face being male and the pipeline connection made through butt welding.