7 replies to this topic

[Araboni]

Dear all We are to design a refrigeration package (incl. Screw compressor) and as per our calculations, both Propane and Propylene work well as refrigerant. But we have experienced that propylene separation from oil can not be done 100% as the propylene is slightly soluble in polyethylene glycol oils. Now I was wondering if anybody has any idea about this issue. regards

[Bobby Strain]

It's probably best to use propane if it fits the application's temperature requirement. My experience is that propylene is used only in processes where propylene is produced. And propane is more readily available than propylene. Probably at a lower cost, too.

 

Bobby

[Araboni]

Dear Bobby ,

thank you for your reply. Attached the calculation and comparison of both Propane and Propylene as refrigerant is given. What is your idea?

Attached Files

•  Propane and Propylene Refrigeration comparison.xlsx   17.28KB   19 downloads

[Pilesar]

A few comments...

1) Your refrigerant will NOT be 100% propane or 100% propylene. The best available propane may be only 90% propane. Allow for the real composition range in your simulation! 

2) If designed for propane, you cannot assume the system will work with propylene. If you want flexibility, put it in your specifications. Some common elastomers used in instrumentation may handle propane but not propylene.

3) Consider there will need to be on-site storage for the chosen refrigerant. Also unloading facilities.

4) Do you know the availability and cost of refrigerant? In most locations, propane would be preferred unless propylene is manufactured at the site.

5) Since you are asking the question, there is obviously no compelling reason to use propylene. The answer is 'Use propane'.

[Araboni]

HI Pilesar

in our plant we have both Proylene and Propane.

[Bobby Strain]

You should also give information about the evaporator. Is it existing? Process temperatures in & out. Your refrigerant evaporator pressure and temperature. The refrigeration compressor supplier usually provides a filter/coalescer to remove oil from the refrigerant. Either from the vapor or liquid.

[Araboni]

Bobby

The evaporator is also to be purchased. Anyway, do you have any experience with solubility of Propylene in oil and the problem of oil degasing at discharge of compressor?

[Bobby Strain]

You should ask your potential compressor system suppliers. You should also evaluate the propane and propylene with the compositions that you have available in your plant. Then determine what your savings might be. You should, of course, use the appropriate suction and discharge pressures consist with the evaporator requirement and condensing conditions. If your potential vendors have no experience with propylene, this may influence your decision. Regardless of what our experience might be.

 

Bobby