ESP lot of ash in penthouse

[SA07]

Hi
We have 2 boilers 185 t/hr steam coal/bagasse with Hamon ESP. We notice lots of ash particles inside the penthouse where there are the isolating ceramic and discharge electrode hammers during annual shutdown. The ash deposit on the ceramic isolators and may cause cracking.

The penthouse is in depression as the ID fan is blowing the flue gas. So we should not expect to see ash moving up inside the penthouse. There is a heater blower fan on top of the ESP which is only used as start up of the plant. During operation, it is stopped. We have noticed there are 3 holes on the metal plate on top of the ceramic isolators with a 20 mm pipe length 100 mm going down. What is the purpose of this pipe? Can we closed the 3 holes? Plz see attached picture.

Has someone encounter this ash problem and how it was solved? Thks

 

[Dhurjati Sen]

You don't have boiler manuals? The answer should be there.

If the ESP is a separate item (not included in the boiler package) then contact Hamon.

Just below the penhouse you have the superheaters, right? Soot blowers don't come in handy?



DHURJATI SEN
Kolkata, India

 

[SA07]

The answer is not in the boiler manual. Boiler was supplied by Austrian Energy & ESP by Hamon. I have already contacted Hamon. They said they must come on site. They do not come every year to do maintenance on site. They are also quite expensive. We do all ESP maintenance work in-house. There is no superheaters below the penthouse. Superheaters are found on the boiler.
Plz see attached a picture of our ESP and the penthouse on the top.

 

[Dhurjati Sen]

In some boilers, there is also an area called pent house just aove the superheaters.

Anyway, that's not relevant here.

Is there a dust catcher upstream of the ESP ?

Actually, I feel there is an issue with the boiler leading to excess ash generation that the ESP can't handle.

Reg. holes, they could be for cleaning.

DHURJATI SEN
Kolkata, India

 

[SA07]

Yes there is a mechanical duster before the ESP.
On coal, all ash is re-injected in the boiler.
On bagasse, part is reinjected in the boiler and part is evacuated.
We have 2 turbo-alternator - boiler-ESP units. Both ESP seem to be working well as the flue gas from the stack is clean and we are within the environment level for dust monitor.

 

[0707]

I think it is for insulators air blowing cleaning.

luis