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

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 (NO2 flue gas) and combustion vibration during the start-up mode (Pout = 20 ∼ 30 and 40 ∼ 45 MW) in comparison with the base mode (Pout = 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 (Pout = 20 ∼ 30 MW). In addition, the characteristic frequency of the combustion vibration was predominantly in the rage fchar = 120 ∼ 140 Hz, which was related to the presence of a cold flow behavior in a PM3 nozzle at Mode 6B (Pout = 40 ∼ 45 MW).