Recent FAC & Oxygen attack in boiler feedwater equipment 6

[countryham]

Can anyone furnish any known recent(documented)corrosion or failures/ explosions in boiler feedwater systems, with or without injuries??I am looking for industrial boiler waterside failures that can be attributed to Flow Accelerated Corrosion in economizers and oxygen attack in either or both the deaerator,economizer and drums, -including oxygen excursions that caused pitting in drums and/or the superheater section---Please furnish an accurate account of the place boiler capacity, pressure, (100-2,000psig)(plant location and name)type of failure and suspected cause, i.e. loss of steam to deaerator,loss of oxygen scavenger, too much oxygen scavenger,type of oxygen scavenger,etc.,etc... or if you know of someone that can contribute to this subject, please ask them to pass the information to john11933@sbcglobal.net... Thanks, in advance, Countryham

 

[unclesyd]

You should contact AI’s from the different insurance companies as they have the latest information as to the losses and usually have good reports. Hartford Insurance used to have a publication with all the boiler/ancillary equipment accidents. Probably 15 years ago there was a push on the inspection and repair of deareators, especially the heavy wall ones, due to failures withe loss of life. There have been several piping (ERW) failures recently, unfortunately with loss of life. I’ve read several reports from different entities on these failures and the recommendations. I’ll look around as see if I still have some of the info.

Here are a couple sources of information.

http://www.nationalboard.org/Classics/articles.html

http://www.babcock.com/pgg/tt/lit.html

 

[pablo02]

Follow unclesyd's comments -- one problem in today's world is that due to competition implications, most utilities no longer report such incidents except to their insurance carriers and to their PUC's when necessary; the old days of learning from others has been severely restricted by the problems associated with the gamesmanship of making money at others expense....

 

[eyec]

there was a economizer feedwater inlet line that let go due to FAC in a Mid-west plant. can't remember the name but i will see if i can find the article someone sent me and forward the info.

 

[kenvlach]

Not sure that people will voluntarily involve themselves in giving legal evidence (or that their companies would allow it).

This book may be useful: The NALCO Guide to Boiler Failure Analysis.
For more information, see

http://www.amazon.com/exec/obidos/ASIN/0070458731/ref=nosim/bookfindercom0e/103-9699820-3504606

 

[kenvlach]

Another book that may help is Metallurgical Failures in Fossil Fired Boilers, 2nd Edn. by David N. French.
See details (including Index) at

http://www.amazon.com/exec/obidos/t...ding=UTF8&no=283155&me=ATVPDKIKX0DER&st=books

Some other books which may help (but don't seem to be available on the open market) are:

Boiler Tube Failures Vol. 1: Theory and Practice: Fundamentals, ISBN: 0803350589,
Boiler Tube Failures Vol. 2: Theory and Practice: Water-Touched Tubes, ISBN: 0803350597,
Boiler Tube Failures Vol. 3: Theory and Practice: Steam-Touched Tubes, ISBN: 0803350600,
by R. B. Dooley with W. P. Naughton,
Publisher: Electric Power Research Institute

Investigating Boiler Failures: A Guide for Building Service Engineers, by D. C. Walker, ISBN: 0860222519,
Publisher: Building Services Research & Information Association

 

[eyec]

the plant that had a FW inlet to economizer line rupture due to FAC was the Pleasant Prairie Power Plant (WEPCO). this happened in 1995. i can find none other with the same failure mechanism.

let me know if you would be interested in the info pack i have and i will send it to you.

 

[countryham]

Thanks, eyec-- I have that one on file....If you have any other similar information, I would certainly like to know about it...As Artemus Ward (1834-1867) once said,--"It ain't so much the things we don't know that get us in trouble. It's the things we know that ain't so".--- Mail toolynox Technologies, Po Box 12241, Beaumont, Texas 77726.. i/c John White

 

[quadswift]

Is that where Rumsfeld stole his award-winning quote from?
Quadswift

 

[unclesyd]

Here is good website that has considerable information.

http://www.structint.com/

kenvlach,
You and others should take a look too and check on MIC information on this site. We had some this bad and worse.
There is something there in 3D that you don’t normally see except in 2D.

 

[Metalguy]

Unclesyd,
That photo of the delta ferrite left from a MIC problem looks just like one from my power plant. Probably is, because we use SI in many cases-especially stress analysis.

That particular case of MIC that left the ferrite behind involved galionella, an iron-oxidizing bacteria. Only oxid. conditions will dissolve the austenite and leave the ferrite, because the ferrite is richer in Cr.

 

[kenvlach]

Thanks, unclesyd. Interesting site, especially to anyone involved in litigation. To help others find the SEM photo, see the article Microbiologically Influenced Corrosion at

http://www.structint.com/tekbrefs/sib96148/.

Metallguy, was that 2205 duplex SS?
A similar SEM photo shows preferential corrosion of &[ignore]delta[/ignore];-ferrite in welded 316 SS -- ASM Handbook, vol. 13A, Corrosion…, p. 407 -- taken from G. Kobrin, p. 33+ in Biologically Induced Corrosion, NACE (1986). In this case, the primary solidification phase is Fe-rich ferrite (with Ni-enriched liquid), so iron-oxidizing bacteria was still the cause. The problem occurred when water stagnated for several months in new, unheated process equipment.

But, MIC is more likely in raw or semi-treated feedwater rather than with treated, closed-loop, industrial boiler feedwater systems, as most bacteria involved are troublesome up to only about 105[sup]o[/sup]F. ASM..., p. 405-6, attributes failures of austenitic SS from Gallionella and Siderocapsa as being due to the use of untreated or semi-treated well or river water. Of course, there are higher temperature bacteria…

Countryham, please give the material(s) involved and minimum feedwater (condensate?) temperature at the point-of-failure.

 

[countryham]

Reply to Kenvlach,--Of course, I am interested in any/all systems that have a proven or highly suspected failure due to FAC in feedwaters,- especially those failures in industrial boiler economizers that are fitted with carbon steel and those ruptures generally in elbos and welds(highly impinged points)where uncontroled/unexpected oxygen excursions have dramatically varied -regularly,over time- by exceeding approximately 20+ppb DO and later reduced below 2ppb DO in deaerator effluents...Especially in those boilers operating from 200-2,000psig.. and particularly ones operating up to 900psig while using sulfites as an oxygen scavenger which is known to react more rapidly than all others (alternate volatle scavengers residuals in the cycle loop) therefore creating significant varing ORP values in economizer influents that,in turn, are results due to adverse affects upon FAC chemistry control in deaerator effluents

 

[Metalguy]

Kenvlach,
No, for this particular MIC attack the piping was 316L. Before this was discovered, and before the plant was started up, I had discovered that the contractor (huge firm) had welded it with 304L. Because there was some Cl in the water (don't remember how much, maybe 500 PPM), I held a meeting with them to ask why they hadn't used 316L filler or better. reply was that "we really didn't need the corr. rest. of 316, and 304 would be fine". Hmm, ok, my next question was "Why did you buy 316 which costs more if we don't need it?". Reply was "We bought a trainload of 316L at a good price-same as 304L." *I* was not pleased with all this, but what could I do?

A few months later our resident NRC inspector noticed water dripping from a tiny hole in a weld. Actually he found a small puddle of water on the concrete floor of a huge spray pond, which cools our emergency diesels and spent-fuel pools. It was the middle of a very hot summer in July, out in the middle of a desert, so he wondered how a puddle of water could be there. Gallionella, that's how! When chem. dept. manager decided not to add biocides, etc. because he didn't know/care about MIC, the bugs held a huge party--which later became his demotion party too. Back to the 304L filler, since that was the site of the attack, not the 316L pipe. *I* was elated-contractor proven wrong, and should pay a bunch! Wrong, microprobe studies showed a lot of Mo dilution into the weld root pass-like 2.5%!

It was the solidif. partitioning of the Cr to the ferrite phase that gave it resistance to the strongly oxid. envirn. under the gall. colonies-their excrement is loaded with Cl.

So now I know a little about bugsh*t as well as bullsh*t!

 

[aybee]

Quadswift...I think the quote was Abraham Lincoln