Output Air Humidity Issue at Bauer Capitano - need help

[superfisch]

Hi,

I´m running my Bauer Capitano C3E with its original Bauer P21 Triplex filtration unit. Humidity of output air doesn´t go below 20mg/m³ air - usually ist should be below 10mg/m³ air if using a new (non-saturated) cartridge. Pressure maintening valve is set to 185bar - I´m using a 225bar safety valve. How can this happen - anything wrong with oil/water seperators (intermediate or final)? Room temperature is about 25°C, I have tried two new (sealed) Bauer P21 cartridges without any difference. How to check seperators?

Thank you for your help!

 

[OkByMe]

Let's try to eliminate the obvious first. How are you measuring the output humidity and do you have auto drain? If you don't have auto drain, how often are you draining the condensate?

 

[superfisch]

I do not have any auto-drain - I´m draining every 15 minutes during operation - and once before I switch the machine off. If it is not used, there is some pressure left in seperators.

Humidity has been measured by an calibrated humidity sensor for high pressure lines that usually is used to check compressor devices concerning permission for commercial use ("TÜV" in Germany). After measuring that high humidity values, another measuring device was used to check values - without big differences. We have been running compressor twice for 45minutes without any (big) change in humidity (twice bcause two different cartridges) - filling panel has been flushed over an additional silencer with pressure maintenance valve (200bar). Usually - this configiration is used for annual checkup for commercial devices. A friend of mine has these measuring devices to check compressors at fire departments - he only measures these compressors. If anything is not as it should be (to much humidity, to much oil, ...) , he just writes a list with issues to be solved before permission to use compressor is given.

 

[Cleavitt]

Well it sounds like the test method is probably accurate. Can you verify that the priority valve on the P21 is actually working? There isn't much to the design of the oil/water seperators so I can't think of any reason for them to be causing the problem as long as there is back pressure. They are basically just empty chambers.

Are you testing this compressor configuration for the first time or has this compressor's output been tested successfully in the past?

If this is the first time the compressor is being tested for air quality it's possible that the P21 filter (even when new) just doesn't have enough filtering capacity to keep up with the conditions because the dwell time is too short. If the air quality has tested successfully in the past, but is now starting to fail, is it possible that you are just encountering warm ambient temps for the first time with this setup? Perhaps the P21 can keep up with the humidity at 15'C, but at 25'C it requires more dwell time.

Either way my first guess is that the P21 is just not adequate to meet the air quality standards with your compressor's output. It is a very small filter.

 

[superfisch]

This P21 setup has not yet been running at this compressor. Usually - a P21 with a working pressure maintening valve (155bar) produces something like 8-10mg/m³ humidity at a Bauer Capitano (value tested at different Capitanos at same ambient conditions). I tried to increase pressure at PMV from 155bar to 185bar without big changes - so I´m afraid there is something wrong with seperator.
This P21 only has to be used for some month - I need some more money to buy a P61 setup (without securus).

 

[Graeme Tolton]

What are your 1 st and 2nd stage pressures? Is there adequate cooling? Good airflow?

 

[clownfishsydney]

How much water/oil is coming out of the different drains?

 

[superfisch]

I cannot tell you the 1st stage pressure, at 2nd stage I have something about 30-35 bar wenn there are 150-225 bar at final stage. Air delivery is about 130l/min - considering age of devoce that seems to be ok. Cooling can be one reason - but temperature of P21 wall is about 40°C (measured via IR thermometer).

Most part of water is comming out of 1.seperator (between 2nd and 3rd stage), a some water comes out of first drain valve of P21. At 2nd drain valve of P21, there is nearly no water soming out.

 

[clownfishsydney]

Sounds like the separators are working okay.

 

[swamp diver]

I would agree with Cleavitt that likely the P21 is just too small a desiccant bed to dry down the air to what you would like to see. Also depending on where you are sampling after the PMV it may be that your distribution line is retaining moisture (i.e. thermoplastic hose). If so you will need to run the compressor for a longer period of time to get rid of the absorbed moisture. You're better off sampling directly off the PM valve if you can and not have any plastic hose between the valve and the sensor. Stainless tubing is fastest to dry down and if you must use a flexible hose make sure it is Teflon lined as otherwise the polymer will retain moisture for hours on end despite the dry air.

We run a two tower Securus and I've measured that it takes at least 2 to 3 hours at 300 lpm with new filters to dry down the chambers from ambient humidity back to 2 mg/m3 after replacing the cartridges. If your combo separator/PMV P21 appliance is leaking back down to ambient pressure between compressor runs then each time the new cartridge will have to re-dry the absorbed moisture downstream of the cartridge. This takes time measured in hours.

I think your ultimate answer will be a P61.