Boiler APH low Temp

[Rupesh29]

We have 60 TPH high pressure boiler. The outlet temperature of air from APH design at 140 Deg C however we got only 110 DegC at full laod. Also addition to this ESP inlet flue gas temperature is also less that is running 120 Deg C. So my question is why this is happened? Is there any solution to increase both the temperature?

 

[mk3223]

It could be many possibilities in process or any combination, which are the great question to the Process, System Control and Ops.

 

[kasiviswa]

Flue Gas inlet temperature to APH, Air flow actual Vs Design needs to be checked. Also, any bypass on the Flue gas stream or Air stream for APH can also impact temperatures of Flue gas and Air stream.

 

[georgeverghese]

Bypass dampers on hot exhaust gas ducting are generally notorious for leakage. This may be simplest to check.
Another reason could be malfuctioning of the electrostatic precipitator upstream of this air preheater, causing fouling of the exhaust side heat transfer surfaces of the preheater.