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deaerator
3

deaerator

deaerator

(OP)
Hello
I was asked to prepared a report regarding comparison between two type of deaerators,the tray-type (also called the cascade-type) and spray-type deaerators.
Can anybody refer me to a guideline or book or any other reference which includes some topics regarding advantages, disadvantages and limitation of these two type dearators.
Also your previous experiences would be appreciated.
Thanks

RE: deaerator

You will find the following article on the Citizendium online encyclopedia to be useful:

   Deaerator

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

RE: deaerator

processengineer1998,
The oxygen removal is an old system, which is still required for most of the steam generation plants. However, times have changed and this expensive method of corrosion control (and limited success) tends to be replaced by a precise /controlled oxygen injection system, in the condensate or BFW. This is particularly important for the supercritical high temp steam, where the corrosion mechanism is somehow different (read about magnetite and hematite formation and control in steam plants).
Note that one of the most important (and expensive) equipment on a steam plant is the deaerator. It is the heart of the plant. Now imagine that in the oxygen injection system developed by russians and japonese, the stainless steel dearerator is completely eliminated, with much better results in corrosion control.
Worth a read.
Cheers,
gr2vessels

RE: deaerator

Tray types have more turndown than spray types, so one factor in your selection depends on how much your boiler load will vary.

Spray types work, and lots are used, but I still favor the tray type.  You always have the ability to operate at minimum load without fear of getting below the threshold of what a spray type will handle.

And, yes, gr2vessels, it was a real kick in the shorts when after all those years fighting the problems associated with DA's they came out with oxygenated bfw.  Go figure.

rmw

RE: deaerator

(OP)
thanks for your nice responses.
but can you direct me to a guideline or book or article?

RE: deaerator

I do not have my copy in front of me, but I would check out B&W's "Steam" first.  It's a great book, especially when you consider how cheap it is.  I'd be surprised if there was nothing in there.

RE: deaerator

Now MJC, that is a limitation I never thought of.  Who would have thought.  Great point.  I thought the ship I was on had a spray type just because the Navy was cheap.  Of course we didn't operate at part load very often, usually they were pushing the he** out of the boilers.  We could make 33 knots on 2 boilers and 36 knots on 4, so they usually just ran 2 and ran them throttles to the wall, (excuse me - bulkhead.)

Back to the OP and serious issues, if you look at the guarantees between the two (assuming this isn't a marine application) you will see that the tray types typically carry a lower DO level.  The sprays just can't get there.

I can remember a book titled; "Steam Plant Equipment".  I think it goes into the two types in detail.  My copy is at the office, so I can't check it for exact title and author.

rmw

RE: deaerator

(OP)
thanks my friends
your valuable ideas really help

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