Air Compressor for 600 CFM, 10 Bar Pressure Continuous Output 3

[edison123]

I am looking for an air compressor (600 CFM at 10 bar pressure) continuous throughput for cryogenic cleaning using dry ice blasting. The usage will be for about 6 hours continuous.

What sort of compressor can give this output, screw or reciprocating type ? Do I need a receiver tank to maintain the throughput ? If yes, what is the recommended vessel volume ?

Muthu

http://www.edison.co.in

 

[crjones]

In any compressed air process there should be a receiver. It should be 1.5 times the demand for constant flow and 3.0 times demand for variable demand. so for 600 cfm (assuming seal level) for constant demand you would want about 83 cubic feet.

The choice of whether a recip or screw compressor with a receiver comes to what is a better fit for you. I have found that for what you are describing I would lean toward a screw compressor.

 

[edison123]

Thank you crjones. How did you get that 83 Cu ft for the receiver ?

I'm not familiar with compressors' efficieny. Could you please tell me why a screw comp is better in this application than a recip ?

Muthu

http://www.edison.co.in

 

[zdas04]

crjones,
For future users of this thread, what time period are you looking at for your 1.5 times the demand? If it is "daily usage" then (600 cfm * 60 * 24 * 1.5 * (1 bara /11 bara) = 118,000 ft^3 or a 48 inch diameter vessel 9,380 ft long). Even 15 minutes at 10 bar(g) or 11 bar(a) the storage volume would be a 4 ft diameter X 9 ft vessel.

From your "83 cubic feet" comment I'm guessing that you mean 1.5 minutes of demand which seems a bit short.

Edison123,
600 CFM at atmospheric pressure into 10 barg is around 175 hp. You can do that with either a dry screw, a flooded screw, or a recip. It is about 8 compression ratios so for the dry screw or the recip you would need to do it in two stages. With a flooded screw you can do it in one stage pretty easy (something like a Gardner Denver SSQ with 4.6 VI) driven by either a 175 hp motor or an engine like a Cat 3306 TA). With either the Flooded Screw or the Recip you'll have to be pretty careful about post processing to keep oil out of your downstream process.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

"Life is nature's way of preserving meat" The Master on Dr. Who

 

[crjones]

zdas04,

The parameters outlined are pretty much a plant air-type operation. So I felt the effort is simply load smoothing.

edson123,
A screw compressor whether dry or flooded is designed for continuous operation. Choking the compressor really makes the efficiency lower. A recip, which has higher efficiency under part load, loses some of this as manufacturer's generally oversize on extended operation. It is really a part load machine. And the valving not on a screw compressor usually requires annual maintenance.

In India, I would recommend you contact Elgi or Atlas-Copco.

 

[edison123]

Thank you zdas04 and crjones. Just got the revised requirement (from the cryogenic cleaning company) that they need only about 220 CFM at 8 bar. That is a steep drop in their requirement.

Just got a quote from Elgi for 2 screw comps - 238 CFM at at 10 bar with 60 HP motor and 295 CFM at 10 bat with 75 motor and a receiver tank of 1000 liters at 10 bar. Do these nos. sound right ?

Muthu

http://www.edison.co.in

 

[dcasto]

I looked at the Sullair site and those are about right for their machines.

 

[dcasto]

before I get away, we could all be way off if your altitude is over a few hundred feet.

 

[edison123]

Thank you dcasto for that confirmation.

Good point about altitude. I am st sea level though.

Muthu

http://www.edison.co.in