Summary

F&F Europe bv, located in Kerkrade, the Netherlands, produces frozen mushrooms in a process involving washing, cutting, blanching (optional), freezing and packing. A central cooling unit produces the necessary cold, with ammonia as a refrigerant.
Ammonia refrigeration systems operate more efficiently when lubricating oil is removed from the refrigerant. Due to relatively high ammonia temperatures some of the oil applied as lubricant and sealant evaporates and is transported into the cooling system by the ammonia flow. This oil contamination causes a film to settle inside the evaporators and condensers, which decreases the heat transfer and causes a fall of the suction pressure, a rise of the condensation temperature and an increase in operation time and electric energy consumption of the compressors.
Previously, the oil was removed in traditional separators. However, due to the high temperature of the ammonia leaving the compressor (over 100 °C in the piston compressor) the existing separators are unable to prevent evaporated oil and small oil droplets entering the system.
The company decided to introduce a hydrotreated oil and a high-efficiency oil remover.
This recently developed type of oil separator has been installed at the discharge sides of the piston compressor. These measures caused the oil concentration in the gas leaving the compressor to drop to less than 3 ppm. Not only does this lead to substantial energy savings, but also to a significant reduction of the oil consumption and a diminished need for maintenance.
Also safety conditions during oil change are improved while the oil contains less ammonia solved. The oil reclaimed from the ammonia flow may be fed back to the system.