Posted by B.T.Bill on May 20, 2001 at 09:29:58:
In Reply to: Hey B.T. Bill posted by Tarzan on May 16, 2001 at 06:54:21:
: Black water problem? Funny I should check the forum today and see your request for update....Our water treatment rep returns today and perhaps he can offer a plausable explaination. After all, it's an opportunity for him to promote yet another expensive chemical to add to our brew. If he can't, I'll attach him to an injection pump and stroke it till he shrugs honestly. The question has us operators resembling Larry, Moe and Curly. The boss has scratched a bald spot and gained 4 strokes on his game. Yeah, we need an answer too.
: The one thing I don't understand about your problem is that this black stuff is carrying over with the steam. During our first couple of years after commisioning our plant (900 psi water tube) our boiler water was always a dark dingy greyish black. Our water rep. said it was normal and should improve over time and it did. Boiler internal inspections revealed excellent passivation and magnetite formation. Samples are pretty clear now with just a slight tint. BUT, we normally don't bottom blow, we have a continuous blowdown line to maintain limits. Blowdown water goes to a heat exchanger and boiler make-up picks up some heat. After being online a couple of years the head gasket on the heat exchanger developed a leak. We tore it apart and it was loaded with black muddy residue like you described. Our water rep. said it was from those first couple of years with the dirty water. Analysis showed it was magnetite/iron. Our steam supplies a turbine generator and we sample our steam. It has always been crystal clear with good purity, even in the days when our water was dark. Thats the one thing that really bugs me about your problem is this carry over. Is it possible a steam seperator fell apart? We have chevrons and cyclones in our drum and on the yearly inspections we check all the nuts and bolts and tighten everything back up. Does the steam line that goes to the oil gun come off the main header or have its own drum connection? One boiler I used to operate had a separate steam line supply off the drum to the atomizer and I could see if you had high water you could get occasional carry over and gradual deposition of the black crap. Enough of my ramblings, I figured I might mention them because of the similarities. Good Luck!
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