5 replies to this topic

[sreekanthtm]

I wanted to redesign the economiser of the furnace.Presently flue gas temperature is 135 degC. So condensation occurs. To prevent this heat transfer area to be increased or tubes to be plugged.I have attached design and actual conditions.

 

Plz help me....

Attached Files

•  economiser.xls.xlsx   9.53KB   91 downloads

[tarafdar]

Hi Sreekanthtm,

 

Both inlet temp. of gas & feed-water is low.But the main problem is feed water temp.,it is 105⁰C instead of 161⁰C.Why you are thinking about redesigning or plugging?Try to increase your feed-water inlet temp.

Thanks.

 

Tarafdar

[srfish]

The economizer will need to be redesigned. The heat transfer needs to be increased because the new conditions are causing a lower LMTD.

[sreekanthtm]

Tarafdar:

 

hi,

 

Since this BFW is coming from another economizer, the temperatire can't be increased.....

Thanks...

 

 

Sreekanth

[sreekanthtm]

SRfish:

 

Hi,

   Can u help me to design the economiser?

[Zauberberg]

I don't think the redesign will help - with regards to condensation on the flue gas side. Feed water inlet temperature is too low and it wil always cause localized sub-cooling (and condensation) in the area of the exchanger where water starts to exchange heat with the flue gas. This phenomenon is known for all air/flue gas and water/flue gas preheaters.

 

What needs to be done, is to raise the temperature of feed water beyond the dew point of flue gas. If flue gas contains SOx, severe corrosion and plugging of economizer tubes occurs. See attached article, and the dew point calculator.

 

http://users6.jabry....athy/dewpta.asp

 

Attached Files

•  Cold-End Corrosion.pdf   101.91KB   45 downloads