Cavitation in Steam Header
Cavitation in Steam Header
(OP)
I have a steam header that is failing every 1-2 years consistently. The steam is part of a cleaning system where 625# steam is blown into atmospheric pressure environemnt where the steam rapidly expands and cleans the carbon build up on the walls.
When not in use the system is closed off a dead leg exists at a highpoint. What I beleive is happening is liquid is condensing and falling back down the line, then flashing when it hits the superheated steam and causing cavitation erosion in the pipe. Is a stainless steel going to remove my problem (currently carbon steel), or will this constant caviation effect eat through stainless steel at a relatively similar rate? Is there any other alternatives?
When not in use the system is closed off a dead leg exists at a highpoint. What I beleive is happening is liquid is condensing and falling back down the line, then flashing when it hits the superheated steam and causing cavitation erosion in the pipe. Is a stainless steel going to remove my problem (currently carbon steel), or will this constant caviation effect eat through stainless steel at a relatively similar rate? Is there any other alternatives?





RE: Cavitation in Steam Header
RE: Cavitation in Steam Header
RE: Cavitation in Steam Header
1. Tiger stripes widespread feature
2. orange peel surface texture where the surface looks black in color (local or general damage)
Cavitation damage -
1. Very rough texture, like the surface of a sponge with sharp edges.
Erosion
1. Can be smooth and higly localized or general damage
For FAC - go to Cr-Mo material (P11 or P22)
For erosion - increase Chrome content to P22
For cavitation - stop the source of water from forming droplets during contact with the surface.
RE: Cavitation in Steam Header
The issue with SS is that while you would get fantastic erosion and cavitation resistance the thermal expansions are much higher. I see thermal fatigue failures in SS regularly.
Sounds like you need to re-route a line to minimize the risk of water returning.
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Plymouth Tube
RE: Cavitation in Steam Header
rmw
PS: the DSH had to be redesigned to take a much higher pressure drop on the water side which kept the water as liquid until it exited the nozzle. But I'll never forget the noise it made.
RE: Cavitation in Steam Header
RE: Cavitation in Steam Header
rmw
RE: Cavitation in Steam Header
RE: Cavitation in Steam Header
How about some pictures of the failed/cavitated metal area ? Can you get ahold of a camera and use it ? Help us out here.... we are trying to help you
Perhaps a sketch of the system showing how condensate repeatedly eroses a section would be helpful.
This type of failure sounds almost exactly like the failures at dripping desuperheaters in fossil power plants. The "fix" for these is usually a change to 2.25 Cr/1 Mo materials
RE: Cavitation in Steam Header
All I have is paint so ive drawn a very crappy brief drawing. General idea is that steam comes off the header into the dead leg area when steam is injected, then is sat idle otherwise the corrosion is right off the header.