we have a centrifugal compressor. Its suction pressure is 55 bars ( T=56°C) and the discharge pressure is 118 bars (T= 120°C).
The DGS is tandem with no intermediary labyrinth.
The DGS is contaminated with the oil carried over with the process gas; this gas is taken from the discharge of the first stage to be used as the sealing gas in the DGS
For a long period of time we have not opened the purging valves scaling of the filters. Could that lead to this contamination? If so, why does the contamination happens always in the drive through side?