Max No. of bank tubes can be pluged
Max No. of bank tubes can be pluged
(OP)
I have water tube boiler and I need to ask about the max. number of tubes in bank tubes (boiler side) can be plugged (due to leakage which difficult to be replaced) that do not cause fail or limit in steam production.





RE: Max No. of bank tubes can be pluged
RE: Max No. of bank tubes can be pluged
RE: Max No. of bank tubes can be pluged
If they are close together then you will run into issues sooner.
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P.E. Metallurgy, Plymouth Tube
RE: Max No. of bank tubes can be pluged
RE: Max No. of bank tubes can be pluged
I would look at the impact of the loss of heat transfer area and impact of velocity through the remaining tubes.
RE: Max No. of bank tubes can be pluged
Hey MF [et al], maybe you can expand my knowledge...
Is not velocity in tubes generally defined by the head between upper and lower drums, the ID of the tubes, and the triad of quantity of heat transferred / amount of steam generated / percentage phase mixture at the upper / exit ends of the tubes? And since all of the foregoing are more or less fixed for a given firing rate, will not the velocity within the tubes remain relatively unchanged?
Maybe it's just me, but it seems to me that a quite significant number of tubes [and those fairly clustered -thanks, Ed] within a bank of them would have to be plugged before a substantive rise in flue gas exit temperature would occur...
If not, please forgive my ignorance; I've been away from steam for a number of years and have only recently started getting back into it, so if I'm the one getting sharpened, it would be dumb of me to complain about it...
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Max No. of bank tubes can be pluged
RE: Max No. of bank tubes can be pluged
Please contact the OEM reg. the number of bank tubes that you can plug.
Also, ensure that there are no roll leaks.
RE: Max No. of bank tubes can be pluged
If you are trying to produce the same pounds per hour through less tubes, you are forcing the same mass through less cross sectional area. Therefore the velocity would increase (or you derate the boiler to produce less steam).
RE: Max No. of bank tubes can be pluged
http://www.eng-tips.com/viewthread.cfm?qid=429627
There are also ASME Code strength issues to consider when plugging.... detailed here:
https://www.nationalboard.org/SiteDocuments/E-Publ...
In my experience,for firetube boilers, I have heard of a general rule of 5 to 7 percent maximum blocked tubes.
It is important to remember that tube plugging is a temporary fix and that the tube should be replaced at the next schedules outage.
Also it is important to note that boilers in cyclic service will tend to loosen their plugs..!!!
Shell & tube heat exchangers operate under different rules and thermal overdesign is common. As a group they are likely capable of a higher percentage of plugging
http://www.trumboinc.com/sites/559/uploaded/files/...
MJCronin
Sr. Process Engineer