Gas Turbine air inlet filters

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Thread Starter

Paragkumar

Dear Sir,

during heavy fog a lot of water mist ingressed in the ailr inlet filter house, is it advisable to stop the inlet air pulsing?
I guess because of wet filters there will be less chance of removal of dust loading from teh filers but it worsens the failure of the filters due to heavy blow of pulsing

Please advise!
REgards

Parag Bhagat
 
Too many variables exist regarding inlet air filters. We call this process "puffing" the filters, because of the sound the process emits.

If the filters becomes wet and then are exposed to contamination, it is obvious this contamination will "stick like it was glued". The air pulses will then find the path of least resistance and tear the weak paper filters.

On the other hand, certain contaminates can be removed while "puffing" offline "dry" and cannot be removed while "puffing" online "dry or wet".

Best practice "for our particular location" is to manually remove contaminants with a broom and vacuum while offline. Our problems exist with the trees. Cottonwood trees flower and emit a soft contamination that "sticks like glue". Online and Offline "puffing" is not effective in our particular location.

Observe what nature hands you and find your best alternative.

Good Luck.
 
Parag,

You give a little information about your filtration system and location. I guess that you have a Donaldson type of filter and On Shore based power plant?

Usually the pulsation system is programmed to operate during the evening’s hours (18.00hrs onwards). Since the humidity will be the maximum at evening hours, moisture will be more. So the first advice to mitigate your problem is:

1) Consider operating the pulse system during the day.

2) Monitor and log the dP and if its increasing to alarm level consider unloading the GT (your boss might not like it).

If you have GE type GT inlet system, usually the GT is protected to avoid implosion of the filter. The air inlet system should have at least one transmitter or switch which is calibrated to alarm and trip value. In general for GT's with 90 to 150kg/s inlet air flow (20 to 40 MW GT), the setting will be for alarm (first up alarm) 65mmH2O and 100 to 120 mmH2O trip. Maximum inlet housing dP should not exceed 150mmH2O. Again those values are site specified. Usually you have also the so called implosion doors. Those doors will be open to avoid implosion thus, the filters will be bypassed and the air flow to your GT will be through these doors (you will have a alarm if these doors are opened). This statement will be valid assuming your IMPLOSION DOORS are properly calibrated.

GOOD LUCK
 
Hai.

I would like to clear two things first.
1) When it is raining are you stopping the pulsing sytem (when the system operates either manually or auto pulsing mode)?
2) Is there any recommendation from the vendor that pulsing should be stopped during the rainy season or foggy seasons?

Coming to the question, we have continuous pulsing systems in our gas turbines and we run the pulsing system continuously. When the wet air is passing therough the filter there is chance for the filter to choke faster than the dry weather. And in this time if we stop the pulsing then the differential pressure increases faster.

We have Braden filters fitted with the Continuous pulsing systems which is running continuously. May I know who is your supplier for the inlet filters?

Coming to the second part of your question, "but it worsens the failure of the filters due to heavy blow of pulsing." I think the pulsing flow will be same even during the rain also, right? Or do your filter systems have any pressure variating pulsing system? If so, can you please mention the details here?

Anyway, I would like to conclude that "if there is no specific requirement from the OEM, then you can continue which would help, otherwise DP will increase faster. As long as you maintain the pulsing air pressures in design limits there would be no harm. If we see they say that these are designed even for snow weather."

Hope to see for more details,

Thanks,
Venkat
 
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Hans-Georg Kwauka

Dear Sir,

Pulsing in humid climates is a useless action. Best is to change out the cartridge filters you are operating with a new generation of depth loading filters like the Eagle Filters Turbomaster. Turbomaster filters are made out of full synthetic filtration material and are water resistant up to 720mm water column. Therefore, these filters make pulsing obsolete. Turbomaster basically have three filters combined into one. One removable hood of either G3 or G4 filter class, a pre-filter of F5 or F6 filter class and a fine filter of F8 or F9 filter classes and can be produced in all shapes (cylindrical, conical and all combinations thereof) lengths and attachment devices.

Please let me know if I can be of assistance.

Regards,
Hans-Georg Kwauka
GasTurbineSupport
Germany
 
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