Hi Everybody. Please receive a big hello from Argentina, South America.

I need some help with a chiller from sabroe (2SAB 163 and 1 SAB128).
the evaporator is a PHE from Alfa Laval MK15 with 70 cassettes. The performance of the PHE is reduced by oil on the evaporator. We are purging an average of 1.5lts of oil per day every week.
To do this we have to stop the chiller for a minimum of 5 hours to let the oil set down.
The recirculation pipe for liquid ammonia is 4in, and as collecting pot it has a T leg of the same 4in diameter.
My impression is that this is to small to separate the oil from the ammonia. Recirculation of ammonia is 3500 kg/h according to PHE calculation.
Suction temperature is -7°C it should be -3°C, discharge 13 bar
Does anybody knows a safe separation velocity for a liquid ammonia to oil separator?
Oil is PAO 68 from york

thank you