gen bank erosion failures bi drum boiler

[feredagl]

All

we run a 35 MWe bi drum boiler that suffers from major tube leaks in the gen bank from what appears to be ash erosion , the failures occur at the base of the mud drum where the tube enters the drum

is the problem due to vortexing around the tubes of ash or is it caused when we soot blow and the ash on the drum literaly grit blasts the tubes away ?

 

[Duwe6]

Low probability that soot-blowing is causing your problem. Put a camera in the wall and watch the dynamics around the tube bases.

"When in doubt, always ask the equipment"

 

[rmw]

Check the original design drawings to make sure that you aren't supposed to have some refractory in that area.

rmw

 

[boilerone]

If failures only happened on a few unique tubes then it could be vortex. The fix is to eliminate irregular tube spacings or arrangements which create gas path channels and allow flue gas to take shortcuts and hit certain tubes at much higher velocities.

If damages including thinnings happened on many tubes and they occurred along the same line and at about the same elevation as sootblowing path, then blame the sootblower. The blower lance being too close to tubes, blowing pressure too high, too frequent blowing and combined with ash erosion like you suspected could be the direct reasons. If you do not want to relocate or remove the sootblower or do other things, you can consider adding tube shields and let them face the sootblower lance.

boilerone