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Ryzac
13-03-2009, 05:02 PM
Greetings,

In my search for info I found this forum and thought I would post and get some thoughts.

We are looking to replace 47 year old York Recip Compressors with Refrigerant oil cooling that are used for Propane Refrigeration.

We had a refrigeration study completed (not much help) that supplied us four budgetary quotes.

1) GEA FES Screw compressor system using water cooled oil cooler.
2) MyCom Recip Compressor system using water cooled oil cooler.
1) York Screw compressor system using refrigerant cooled oil cooler.
2) Vilter Recip Compressor system using refrigerant cooled oil cooling.

Needless to say, 4 quotes, 4 options, and the screw options are quite a bit more than the recip options.

What are your thoughts on the

1) Manufacturers?
2) Screw vs Recip for this application
3) Water cooled vs Refrigerant cooling systems

Our current system is most similar with Vilter option.
Of course we have to weigh the upfront cost of the screw with the maintenace cost of the recips.

Thanks for any advice and feel free to ask for more info if needed.

CHIEF DELPAC
13-03-2009, 05:33 PM
Ryzac It sounds like your company is like my employer, they want to get the maximum life out of their equipment. Not knowing anything about your site or operating conditions,I would stay away from water cooled oil coolers because of the risk of corrision which in time could lead to the failure of the oil cooler allowing the oil to be contaminated with water. Also there is the added cost of water treatment, sewer rates, and cost of the water. I will admit that I have bias toward thermosyphon oil cooling as it is trouble free And does not require a lot of maintenance. C. D.

RANGER1
13-03-2009, 10:16 PM
Rysac ,
What model and size MYCOM/VILTER also speed is being offered ?
If speed is kept below 1000rpm should be no problem .
Also Mycom should be able to offer refrigerant cooled oil cooler and doubt heads need any water cooling on this duty .
Both good quality machines , the slower the better .

Ryzac
17-03-2009, 03:28 PM
More details on the units are:

1) GEA FES Model 85GSB and 55GSB Screw compressor system using water cooled oil cooler.
2) MyCom Model P6WB-50 and P6WA-75 Recip Compressor system, 1200 RPM using water cooled oil cooler.
1) York RXF-50 and RXF-30 Screw compressor system using refrigerant cooled oil cooler.
2) Vilter Model P12B458XLD and P12K454XLD, 1200 RPM Recip Compressor system using refrigerant cooled oil cooling.

We will be looking at 2 of each for a total of 4 new compressors. Normal mode would be one set running close to 75-100% during summer and running 33-66% winter. 2nd set of compressors would be back up and additional refrigeration for our filling process.

Is there an issue with the unloading of the Recips as far as running unbalanced increasing wear? That was stated by one of the Screw Compressor reps.

We will not be going with water cooled and i think they all offer refrigerant cooled options.

Thanks for the feedback

US Iceman
17-03-2009, 04:23 PM
Is there an issue with the unloading of the Recips as far as running unbalanced increasing wear? That was stated by one of the Screw Compressor reps.


No. That's a bunch a crap. And... the part load performance of a recip. compressor is a LOT better than a screw. Typical screw salesman...:(

The Vilter model numbers you provided say they are operating at approx. 1200 RPM. I agree with Ranger1; use a slow speed compressor preferably around 1000 RPM or less. The models quoted to you are direct drive so if you stick to this you will be limited to 1200 RPM (6 pole motor @ 60 Hz) unless you can allow belt drive. Something to look at....

The refrigerant cooled heads and oil cooler is a good idea to use. Vilter will probably provide DX cooling for this purpose, but I have used thermosyphon cooling on these compressors before with propane (on an off-shore gas platform).

Magoo
18-03-2009, 04:22 AM
If it is not broken , rebuild it. there is nothing wrong with old well built plant. Perhaps these new hi efficiency motors can help. Why try and re-invent the wheel, all suppliers will fill you head with garbarge for there own end.
magoo
magoo

danod
23-03-2009, 05:26 AM
Greetings. Is this propane refrigeration by chance for Gas plant application? Mycom does have oil coolers for propane. I work on them all the time. As far as running unloaded I have come across hundreds of Mycoms and Vilters that run that way. ie. 12 cyl running on four or 8 running on 2 cyl. Recently retubed a Mycom 12/4wb to completely unload on low stage side. Also work on Vilters and Mycom screw compressors.

Ryzac
10-04-2009, 02:39 PM
If it is not broken , rebuild it. there is nothing wrong with old well built plant. Perhaps these new hi efficiency motors can help. Why try and re-invent the wheel, all suppliers will fill you head with garbarge for there own end.
magoo
magoo

Unfortunately because of very old equipment, harder to aquire parts and the outsourcing of oil pumps, we need to either completely overhaul our current compressors or replace with new. The cost of parts is much greater than buying new. We are leaning towards recips since we did get such long life out of current recips and hard to justify the increased capital of the screws.

We also want to take this oppotrunity to double the capacity of the electric compressors as we have an equally old pair of Roiline Engines Compressors that are used which we would retire.

sterl
10-04-2009, 06:04 PM
Interesting collection of pieces.

The oil cooling, and oil recovery, situation is of some import here. Some of these are sleeve bearing machines and pretty sensitive to a refrigerant wash through the galleys.

Presuming your piping details and layout is such that you have good oil return or otherwise good oil management in place, it may not be of great concern to you: but the screw packages come with some pretty high end versions of oil separation, filtration and cooling....and at least the Frick machines do not have full time oil pumps.

A recip can have the same type of oil conditioning applied but the higher discharge temperatures make it all a little more difficult and the "normal" pieces aren't as good.

And if Part Load performance of the screws is of substantial concern (and it is better now than it once was) consider the advantages of variable speed drive. Frick refers to it as a Viper Drive. They will flat line your suction pressure to an accuracy that controls on a multicylinder just won't permit.

RichardRobinson
16-06-2009, 04:30 PM
Can I use Hitachi horizontal scroll compressors on R290?

Brian_UK
16-06-2009, 11:15 PM
Can I use Hitachi horizontal scroll compressors on R290?
What do Hitachi say about it?