Screw compressor, oil flooded or oil free

[payaam2000]

Dear All

Please advise me if I can use oil flooded screw compressor for a contaminated sour gas with high content of H2S (for recycling the sweep gas).

Some suppliers recommend to use oil free compressor but I doubt they desire to sell a more expensive oil free compressors.

Is there any body who could advise me if there is a practical guide (or handbook) for using contaminated sour gas in oil flooded compressors?

Thanks

 

[gwalkerb]

When you say contaminated, are you referring to anything other than the H2S content? Oil-flooded screws can certainly be used in sour gas service, but what's your concentration?

Frick screws I know can be installed for sour gas service, although I'm not sure of the maximum concentration. Basically, with an oil-flooded screw, the primary concern is just keeping your gas above the water dewpoint at all times. This is a concern for any oil-flooded screw, but especially when there are corrosive substances such as H2S or CO2 in the gas stream - if water condenses, and those form carbonic or sulfuric acid, there can be issues. But if you keep things hot, there's no reason an oil-flooded screw can't have a long service life in such a service.

I would check with a manufacturer or packager for screw compressors, and find out what they can offer for sour service screw compression.

 

[SaraChem]

how sour we are talking? 50% H2S or 2%? concentration can have a large impact
I have used Frick and Leroi in sour packages, as gwalkerb mentioned above, check your dew point so you wont run in oil dilution issues that might break up your machine. I have only used oil flooded type screws

 

[frankm07]

Like gwalkerb and SaraChem said, Frick screw compressors can handle H2S gas. You just need to make sure either there is no water content or the pressure and temperature are high enough so no condensate can form. Frick compressors are the best in the industry. I know that because I was part of the team that designs those compressors. Now I work for York chiller solutions. But I still work with Frick team to solve problems. Let me know if you have any questions.

 

[Mech199]

Due to high sour content Is there any possibility of oil contamination and frequent oil replacement? Also disposal of the contaminated oil is another concern. I understand Frick compressors are used successfully for sour services, i would like to understand how oil contamination issue are addressed?