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Air Preheater Tubular vs Regenerative?

07/31/2017 11:01 AM

Why regenerative air preheater preferable when the transfer of heat in element isn't isolated between flue gas and cold air causing the quality of cold air bad having conveyed the dust/particle from the element. Thank you

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#1

Re: Air Preheater Tubular vs Regenerative?

07/31/2017 11:22 AM

Bad design? Who knows...

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#2

Re: Air Preheater Tubular vs Regenerative?

07/31/2017 12:18 PM

... dust/particle from the element.

I take it you may have a plate type regenerative heat exchanger.

and If I understand what your trying to say is that it sounds like one of your barriers that supposed to keep things isolated are cracked or failed.

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#3

Re: Air Preheater Tubular vs Regenerative?

07/31/2017 12:30 PM

The preheater is supposed to transfer heat from the gas going out to the air coming in so that heat is not just thrown away. There should be no exchange of gases. If you have bad air coming in, you should investigate immediately for a leak.

http://engineering.myindialist.com/2013/to-study-the-working-and-function-of-mounting-accessories-in-boiler-bme-lab-manual/#.WX9aY4TyvIU

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#4
In reply to #3

Re: Air Preheater Tubular vs Regenerative?

07/31/2017 12:37 PM

having designed these things,... it very hard to have a counter flow regenerative HXchanger. Unless each tube has packing to compensate from expansion.

And if the tubes are welded to the tube sheet, which I have seen, even though the ΔT may not be much, it still can crack between the tube and tube sheet.

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#5
In reply to #4

Re: Air Preheater Tubular vs Regenerative?

07/31/2017 1:18 PM

Good answer!

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#6
In reply to #5

Re: Air Preheater Tubular vs Regenerative?

07/31/2017 1:21 PM

Thanks,... btw way... the tubes can be welded on one end, while the other end would have the packing to make up for expansion.

I have designed them for a 1500ºF abouts....

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#7
In reply to #4

Re: Air Preheater Tubular vs Regenerative?

07/31/2017 6:54 PM

the design similar like this sir

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#8
In reply to #7

Re: Air Preheater Tubular vs Regenerative?

08/01/2017 4:00 AM

Nice to finally know just what you are talking about.

<Frownie Emoticon> says: "Why didn't you provide this in your Original Post?"

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#9
In reply to #7

Re: Air Preheater Tubular vs Regenerative?

08/01/2017 10:24 AM

In the design selection phase, perhaps the warmed cooling air was intended to go to some process where carryover was not important, or as PWSlack posits in Reply #1, the sealing efficiency was not as expected, and the suspended solids in the hot gas stream were not expected. Perhaps a sector gas purge between the hot & cold side seals is not working, or provided...

Discounting shortfalls you have observed, it's likely that the installed cost vs thermal transfer efficiency pointed to the design you have.

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#10
In reply to #3

Re: Air Preheater Tubular vs Regenerative?

08/01/2017 9:06 PM

isn't that a tubular design sir? which is the cold air are isolated from flue gas

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#11
In reply to #10

Re: Air Preheater Tubular vs Regenerative?

08/02/2017 7:02 AM

tubular of plate doesn't matter the concept is there. The cold air is isolated from the flue gas by the tube sheets. where one end the tube sheet is welded to the tubes, the other end the tube sheet is sealed with packing between the tubesheet and the tube.

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adpabd (2); James Stewart (1); Mikerho (1); phoenix911 (4); PWSlack (1); Rixter (1); rwilliams (1)

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