The session chairs and discussion leaders for the LM6000 sessions were Bryan Atkisson of Riverside (Calif) Utilities and David Merritt of Kings River Conservation District. The morning session included users and depots; users, depots, and OEM participated in the afternoon.
The DLE engine is growing in popularity. Today about 25% of the turbines in the LM6000 fleet are of the dry, low-NOx type.
Good news for users: Repair procedures now are in place for all SKF MRC bearings except 4B; previously there was a repair procedure for only one bearing. A benefit of repair, one user said, was a cost saving of about 50% on the price of a new bearing. This is incorporated into the Industrial Repair Manual approved by the OEM.
More good news: Combustor issues are being resolved. Historically the combustor was a hot topic with discussion on fuel nozzle/primary swirler wear, splash plate oxidation, and secondary swirler TBC spallation. The G42 combustor has dramatically reduced splash plate oxidation and spallation now is rare; primary swirler wear has been reduced but still in evidence. SL-6000-02, issued in mid 2010 offers guidance on combustor designs best suited for specific plant operating conditions.
Interestingly, for virtually every issue raised, owner/operators asked about the duty cycle, operating hours, and starts to gauge how concerned they should be regarding the potential impact of that issue at their plants.
The LM6000 has been in service for 19 years and the OEM recently shipped its 1000th unit. Many engines are approaching the critical time for decisions regarding replacement of parts.
Lay-up of peaking units generated discussion regarding periodic cranking of the engine to wet bearings. Intervals vary by user and range from about one week to one month. Trend is to shorter intervals to avoid corrosion and bearing issues.
Sprint water leaks have been reported along the split line. Clogged nozzles are one reason. Solution: Loosen bolts and tighten in order recommended by the OEM to reduce leaking. Inspect nozzles regularly and consider periodic flow testing.