Abstract: This paper analyzes the causes of dry gas seal failure during the start-up of centrifugal recycle hydrogen compressor, and concludes that the liquid entrainment in recycle hydrogen and the fast speedup of compressor unit are the direct causes of dry gas seal failure. The liquid entrainment in recycle hydrogen does not necessarily damage the dry gas seal. When the unit runs at a low speed, the liquid in the recycle hydrogen does not gain enough energy to enter the seal chamber due to the obstruction in labyrinth seal and first-stage seal gas, so the dry gas seal is not affected. Only when the rotation speed is high enough, the liquid in the recycle hydrogen can enter the compressor outlet seal chamber, causing damage to the dry gas seal. Therefore, if the dry gas seal is not affected after the naphtha enters the centrifuge, it is not necessary to dismantle the machine for repair.

Key words: centrifuge, dry gas seal, liquid entrainment, reason, countermeasure