I
Gas Turbine: GE frame 7 Hydrogen Leaking
History FYI:
* Field went to ground three months after a major overhaul on turbine/generator
* unit repaired - Unit passed leak test -Unit ran several times
* hydrogen started leaking
* hydrogen seals found kicked
* repairs made to seals
* leak test passed but not great
* noted seal oil flow meter running 1 GPM
* past history reports shows 30 GPM for several years
* try to perform SHAFT SEAL FLUID CHECK per book but oil and hydrogen started blowing out around the seals abort test
* engineers stated normal seal oil flow due to machine tighter than before
* ok to run - repaired some small leaks on hydrogen system - run machine several time
* H2 leakage started to degrade
hydrogen leakage:
* 6.5 lbs in 9 hours
* note hydrogen sense in the main lube oil tanks and in the cooling water head tank with detector
* valve out all the coolers to verify as major leak - still leaking
Today we have the seals apart looking for concern.
Question:
Is it normal to have hydrogen detected in the main lube oil tank?
What should the seal oil flow be?
Should the air side seal have a bigger gap than the H2 side?
During the SHAFT SEAL FLUID CHECK is oil and hydrogen blowing out around the seals normal?
Any input would be greatly appreciated.
History FYI:
* Field went to ground three months after a major overhaul on turbine/generator
* unit repaired - Unit passed leak test -Unit ran several times
* hydrogen started leaking
* hydrogen seals found kicked
* repairs made to seals
* leak test passed but not great
* noted seal oil flow meter running 1 GPM
* past history reports shows 30 GPM for several years
* try to perform SHAFT SEAL FLUID CHECK per book but oil and hydrogen started blowing out around the seals abort test
* engineers stated normal seal oil flow due to machine tighter than before
* ok to run - repaired some small leaks on hydrogen system - run machine several time
* H2 leakage started to degrade
hydrogen leakage:
* 6.5 lbs in 9 hours
* note hydrogen sense in the main lube oil tanks and in the cooling water head tank with detector
* valve out all the coolers to verify as major leak - still leaking
Today we have the seals apart looking for concern.
Question:
Is it normal to have hydrogen detected in the main lube oil tank?
What should the seal oil flow be?
Should the air side seal have a bigger gap than the H2 side?
During the SHAFT SEAL FLUID CHECK is oil and hydrogen blowing out around the seals normal?
Any input would be greatly appreciated.