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Little Prince
21-05-2013, 03:59 PM
We have a R1270 refrigeration cycle with Howden oil injected screw compressor and we decided to install a oil reclaimer heat exchanger to recover dissolve oil. On shell side cold liquid refrigerant with dissolved oil is placed and on the tube side hot R1270. The task was to increase the cold side temperature to reach its Dew point and separate oil from Refrigerant. But here comes the problem. Is there any alkylic bond made between oil and refrigerant? (HEX manufacturer claim)
Isn't it true that no bond should be made between compressor lubricant and medium of compressor?
Please advise.

ISEL
06-06-2013, 02:36 PM
In a industrial cooling system with an oil separator - like what you are installing - you want your lubricant to be immiscible. This is important on the evap side. With systems not equipped with oil-separation capability, the lubricant carried over from the compressor into the evaporator must be sufficiently miscible with the refrigerant at the evaporator temperature so that the refrigerant fluid–lubricant blend remains in one phase after expansion in the evaporator and at a sufficiently low viscosity to travel through to the compressor. If the fluid isn't miscible enough - it separates and fouls the evaporator.

The solubility of the fluid is also important. Higher solubility of your lubricant will dilute the viscosity to a greater extent. This will lower the usable life of your fluid as well as increase compressor wear.