The tuning methodology of a GE 7FA + e DLN-2.6 gas turbine combustor

Abstract

On the basis of a MARK-VI system, the tuning methodology for operation of a DLN-2.6 combustor was studied for the maintenance of a GE 7FA + e gas turbine at a Seo-Incheon combined cycle power plant. The DLN-2.6 combustor has a high level of yellow plume (NO 2 flue gas) and combustion vibration during the start-up mode ( P out = 20 ∼ 30 and 40 ∼ 45 MW) in comparison with the base mode ( P out = 100 ∼ 160 MW). The objectives of the current study are to investigate one of the main factors for this high level of yellow plume and combustion vibration during the start-up mode and to suggest the operation strategy for the reliable working of a GE 7FA + e gas turbine. After analyzing the tuning data in a MARK-VI program, we conclude that the yellow plume is caused by the relatively rich mixture ( ϕ ∼ >0.5) in a PM1 nozzle at Mode 3 ( P out = 20 ∼ 30 MW). In addition, the characteristic frequency of the combustion vibration was predominantly in the rage f char = 120 ∼ 140 Hz, which was related to the presence of a cold flow behavior in a PM3 nozzle at Mode 6B ( P out = 40 ∼ 45 MW). ► The tuning methodology was investigated in a GE 7FA + e DLN-2.6 gas turbine engine. ► In Mode 3, the yellow plume was related to fuel to air ratio in a PM 1 nozzle. ► In Mode 6B, pressure fluctuation was caused by the cold flow in a plenum chamber. ► The equivalence ratio in a PM3 nozzle during Mode 6A was related to dynamic pressure.