So, on our two frame 7 gas turbines (DLN 2.0 using quat, Mark V) we have manual tuning valves on coming off the secondary gas line to the fuel nozzles. Typically we don't touch these tuning valves. We leave them at roughly 8 turns open. That was fine when running our older 8k hardware, but now we've finally transitioned to 12k hardware. After a few discussions and research on the use of the valves, it's been brought to our attention that these valves should be open 12 turns for the 12k hardware.

That seems simple enough, but the overall plant knowledge of these valves, and how/why they are used is minimal. After speaking with a neighboring plant that has similar tuning valves, I learned that one of their managers uses them periodically to adjust individual can dynamics while online. They have about as much literature as we do on the use of the tuning valves, which is essentially zero. I've looked for two days online trying to find any documentation on the tuning valves and their proper use but have not been able to find anything.

Does anybody have any information on the operation of these valves that they are willing to share?

 

The tuning valves were provided to provide dynamics tuning (by a qualified tuner) for individual cans. The change from nominal 8 turns open to nominal 12 turns open was made for the 7FA DLN-2 when changing to "faired" fuel nozzles. Faired nozzles were introduced about 20 years ago. The change from 8 turns to 12 turns changes the flow reduction from a 4% reduction to a 2% reduction. Note the tuning valves are reverse operating, turned counter-clockwise to close and clockwise to open. I'd check with GE to see if this is still the recommendation. If it is, you wouldn't want to do it until the next combustion outage. (If the valves haven't been overhauled at each combustion outage, they might not move anyhow.)

 

Thank you for your reply!

The reason for the sudden interest is that we just am out of an outage, where we swapped from 8k two piece nozzles to newer 12k single piece hardware. We know the valves manipulate correctly, but nobody on site has any actual literature describing the correct procedures involved in manipulating them. We have an ECOmax system that was installed two years ago, but occasionally still have issues with individual can dynamics that ECOmax fights because of our limitations with the system.

My interest is to help the units operate more efficiently, and cleanly and if we can improve the dynamics on the cans individually we could save ourselves some potential hardware issues.