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Looking for reasons why a GE 7EA DLN1 will go into extended lean lean firing mode, at or near base load.
Unit would do this every 3-4 months for the past couple years (more so in winter months). Since a major overhaul this past summer (installed refurbished HGP parts, refurbished combustion hardware, new fuel gas valves, new IGV actuator and calibration of all valves/IGV/transmitters) the lean lean events are more frequent, every few weeks or less.
Tuning shows higher than usual NOX (high 30’s minimum) and low CO (single digit ppm). Moving fuel spit any where’s from 81 to 78 doesn’t resolve issue. Exhaust thermocouples and low spreads do not pin point any specific burner issue.
Points being trended in high speed view 2 files do not pin point any probable causes.
Unit runs on pipeline spec natural gas and base loaded sister unit in plant does not have similar problem.
Looking for suggestions as to what we could try or look at next.
Unit would do this every 3-4 months for the past couple years (more so in winter months). Since a major overhaul this past summer (installed refurbished HGP parts, refurbished combustion hardware, new fuel gas valves, new IGV actuator and calibration of all valves/IGV/transmitters) the lean lean events are more frequent, every few weeks or less.
Tuning shows higher than usual NOX (high 30’s minimum) and low CO (single digit ppm). Moving fuel spit any where’s from 81 to 78 doesn’t resolve issue. Exhaust thermocouples and low spreads do not pin point any specific burner issue.
Points being trended in high speed view 2 files do not pin point any probable causes.
Unit runs on pipeline spec natural gas and base loaded sister unit in plant does not have similar problem.
Looking for suggestions as to what we could try or look at next.