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High Inlet Air Filter Differential Pressure During Rain
Frame 6B machine inlet air filters differential pressure increases significantly during rainy season causing trip.

We are having three gas turbines of frame size 6. Each turbine uses paper filters causing differential pressure becoming high up to 130 mmWC during rainy season. Machine trip on high inlet air filters DP is at 200mmWC.

kindly suggest some idea to prevent moisture ingress into the filters.

Can you give us some more information on the type of air filtration system that you have installed. Is this a self cleaning (Donaldson) system or a traditional changeable element system? Do you have a rain hood or rain eliminator segment installed?

>Can you give us some more information on the type of air
>filtration system that you have installed.


Outside Diameter: 323.72 mm.
Inside Diameter: 212.17 mm.
Height: 700 mm
Surface Area: 242 Sq. Ft.
Air Flow Capacity: 650 CFM (Approx.)
Pressure Drop 25mm W.C across Filter

> Is this a self cleaning (Donaldson) system or a traditional
> changeable element system?
yes it is self cleaning system

> Do you have a rain hood or rain eliminator segment installed?
No

Difficult, I've had this problem in a few places. If these are vertical mounted filters sometimes you can build a screen to protect the filters from the rain particularly if you have a predominant prevailing wind direction. Even high humidity, particularly early in the morning, is going to cause this problem. You can lose even 20% output until the humidity clears and the filters dry out. Really, it is not the best filter for a wet and high humidity area.

By senouci sadek on 23 July, 2017 - 3:06 pm

Hi- kh000,

My idea is only as proposal to mitigate the impact of high humidity in you filtration Dp. as exhaust air in the axial compressor for bearing seal also for cooling system, try and look if some quantity can be flows to intake filter at least to dry and remove the humidity.

you can share this proposal with GE and look for him reply.

other you can use dark louver with optimised angle to evaporate air at this section inlet pass (so hot passage ). i think that also are used by GE.

For the both case you have to concerte with GE to avoid any over consumption of air or overheat in some area.

Hope that can give you some help .

Best Regards.

I'm sorry but this just won't work with self cleaning filters. It is far too complicated for a simple problem. The best solution is try and keep some of the rain away from the filter.

By Curtis Loftin on 25 July, 2017 - 7:15 am

How many hours are on the filters and what environment are they in? When I've seen this happen, the moisture in the air combined with the dirt on the filters and made mud.

The only solution is to change the filters. In the interim, a few filters can be removed. Once the new filters are in, a pre-wrap may help in the future.

Either way, a water wash may be needed afterwards to restore lost power.

ambient temp during rain is about 26-29 degC here. I am thinking to put portable hot air blowers which will throw the air at a temperature of 50degC and cause the equilibrium temp to become around 38 degC. It will remove the moisture in filter surrounding and also will not reduce compressor efficiency.

is it ok?

1 out of 1 members thought this post was helpful...

Yes Curtis, it is a question of maintenance.

I have had exactly the same problem. You must keep the filters as clean as possible when they are dry by forcing a blowdown or the exterior dust will absorb the moisture and block the filters. You can blow them down again when they are dry, also you should shutdown the blowdown during heavy rain as the wet filters can damage easily.

All it needs is some procedures and some vigilance.

We don't seem to be getting much reaction from the original questioner.

sir,

kh000 and khoriwal000 both are same.

ambient temp during rain is about 26-29 degC here. I am thinking to put portable hot air blowers which will throw the air at a temperature of 50degC and cause the equilibrium temp to become around 38 degC. It will remove the moisture in filter surrounding and also will not reduce compressor efficiency.

is it ok?

1 out of 1 members thought this post was helpful...

The main thing is the filters need to be as clean as possible. Do you manually blow them down when they are dry? I had exactly the same problem in Brunei where the ambient and rainfall are pretty well the same as you.

I don't think that your hot air dryer is a very good idea. I think that you will maybe cause a bigger problem by "baking" the wet dust onto the filter. I found that when I had high humidity or rain that I was losing about 15-20% output for about 3 hours under the worst conditions.

The two main things are cleanliness and don't blow down during rain (switch it off!).

By Bob Reinhardt on 9 August, 2017 - 9:45 am

I received this link from our engineering staff that monitors this blog for quality issues and wanted to offer up assistance. I am the Field Service Manager at Donaldson - Gas Turbine Systems and we have several options of filter upgrade that would handle the moisture events better than a paper or cellulose filter. Also by understanding what type of inlet house you have there are ways to mitigate moisture before it even reaches the filters. Please respond to my message and we can discuss this further.

All the best,

Bob Reinhardt

sir, please write the info required.

By Bob Reinhardt on 11 August, 2017 - 10:30 am

What plant are you located at? There are many site-specific details to consider and I would be happy to speak with you regarding these.

We have solutions for most causes of moisture ingress but would need to dig into the site conditions in order to properly asses your scenario. Feel free to contact me via the Donaldson GTS main line at 1-800-431-0555.