Compressed air system

[KrisB4]

Hi,

My company is building new factory, at the moment we are to decide on equipment supplier (Kaeser or Atlas Copco, which are the biggest in Poland).
We are installing either one 24m3/min plus one 14m3/min and another 24m3/min later or two 14m3/min now and one 24m3/min later.
My question is whether to choose a compressor with integrated dryer or to have stand-alone unit.
For me integrated one is better because of simpler installation (in stainless steel), as compressor-dryer connections are internal with built-in oil separator and by-pass.
But I've heard (with no arguments) that it is considered as a worse solution.

Best regards,

Kris

 

[UtilityLouie]

I've used the Atlas Copco watercooled compressor with MD heat of regeneration dryer with great success. When I used them they provided a detail and connecting piping for a combined install. I know they have been developing a packaged unit. If they have, I'd use it.

Being a brand new facility - start off on the right foot and use heat of regen dryers. This is also a large system so they make even more sense.

 

[irishal]

We have a Kaeser supplied system at our site and so for has proved reliable. It has the stand alone dryer arrangement and although it has a much larger foot print, it is maintenance friendly.

 

[bulkhandling]

You may have to define the quality requirement for your compressed air first. The normal classes can be : a. not dried (water or air cooled only), b. dew point to about 2C, c. dried to -40C.

Instrumentation air requires dried to -40C (per standard I follow). Normally you only require part of your total air be dried to this standard, so a separate dissicant drier shall be used for that purpose.

If all your air is required to be dried to 2C, a integrated refrigerated dryer can be used.

 

[KrisB4]

For some lab application we'd require -40C, but mostly 2C dewpoint.
So it'll be refrigerated fro 100%^ flow + desiccant just for lab.
I am mostly looking for Kaser/Atlas opinions as well as stand alon/integrated dryer

 

[KenRad]

I have used the Atlas Copco flooded screw compressor packages that have an integral refrigerated dryer for 10 years. They have, by far, the best maintenance record of any compressors at my factories. We do very little to these things, and they run continuously. I would highly recommend them.

They take up less floor space than a separate compressor and dryer would. Installation is simpler, since the dryer controls are already tied to the compressor controls, there is no field piping to be done between compressor and dryer, and no separate dryer power feed. You also have single source responsibility for all the equipment.

What were the reasons given by those who advised you against the integrated packages? I'm curious to know.

---KenRad

 

[KrisB4]

This is the best part:
No actual reason against integrated packages, except, that "they are considered as a technically worse solution".

There was also an argument that Atlas compressors use 8% more energy than Kaeser, but when I checked installed power or 24m3/min compressor it was 135kW in case of atlas and 139.8kW from Kaeser (one motor more).

 

[crjones]

If you go from the compressor to a receiver, you will drop out most of your moisture there. Then go to the dryer. You will lower the load on the dryer. You need a receiver in the system anyway.

 

[KrisB4]

I prefer to have receiver after dryer, so it smoothens out the peakload from the net, thus providing more stable operation of comressor/dryer.
AFAIK if the the dryer is after receiver, and there's a peak load the dryer may be overloaded, and will not remove enough moisture.
We're gonna have two 5m3 receivers in parallel.

 

[Ashereng]

I also prefer dryer to receiver.

 

[KenRad]

Another good reason for having the dryer upstream of the receiver is corrosion. I've seen 1100 gallon receivers that had 10 gallons of rust particles on the bottom because of the constant wet air environment. This doesn't happen when the dryer is piped upstream of the receiver.

---KenRad

 

[bulkhandling]

My selection can be: compressor+refrigerated dryer -> large receiver -> dissicant dryer -> small receiver.

The large receiver is for overall demand for normal standard air. Smaller receiver is for instrument air. The receiver after dessicant dryer is required to smooth the peakload for the instrument air so that you do not have to size a huge dryer for the peak demand.