LNG multi-stage pump leakage

Thread Content

This post was last edited by Doing things randomly and carelessly on 2016-11-23 at 22:06. The two LNG cryopumps in the plant have been in operation for over 5,000 hours; their bearings have reached 90°C and therefore need to be replaced. Both pumps were taken apart for maintenance. After the first pump was repaired and put back into operation, a leak was detected; at a temperature of -100°C in that leaky area, the bearing temperature was around 64°C. After forced operation for 10 days, the leakage disappeared; the temperature of the leaking layer was -35°C, while the bearing temperature was 45°C, returning to normal levels. The bearing of the second cryopump also needs to be replaced, and after maintenance, leakage occurs just as it did with the first pump. Upon inspection, the leakage point of the second cryopump is at the shaft seal; the temperature of the leakage area is currently around -70°C to -110°C, while the bearing temperature is 50°C. Was the manufacturer’s reply liquid oxygen? He said that after the pump was repaired, air was present inside it, and this air turned into liquid oxygen when it came into contact with the low-temperature LNG... Since the repair, the pre-cooling pump has been leaking continuously; there’s so much liquid oxygen involved. Seeking an answer...