The combustion tuning methodology of an industrial gas turbine using a sensitivity analysis

This paper presents the results of combustion performance testing of a 5.25 MWe industrial gas turbine which features a conical counter-flow double-swirl stabilized, premixed combustor and the Combustion Tuning methodology using a Sensitivity Analysis (abbreviated to CTSA). The combustion performance test was conducted in an atmospheric pressure, optically accessible, real engine scale combustor. The atmospheric rig and real engine correlation was verified by comparing real engine data which were gathered from high pressure tests. NOx and CO emissions, combustor temperature at the fuel nozzle, dump plane and exhaust, dynamic pressure and flame structure, using planer laser induced fluorescence, were investigated with respect to power load and ambient temperature. To enhance the NOx and CO emission performances with stable combustion, the relative sensitivities of five control parameters were analyzed, and on the basis of sensitivity analysis data, combustion tuning testing was conducted. By using the CTSA, NOx emission in exhaust gas was reduced from 18 to 2.2 ppm at base load, with high combustion efficiency (>99.9%), and very little pressure fluctuation (Prms < 0.1 kPa).

► A tuning methodology of gas turbine combustor using sensitivity analysis is proposed.
► Ambient pressure combustion test was conducted and rig–engine correlation was verified.
► Combustor's vital control parameters and their priority were determined by sensitivity analysis.
► Pilot to total fuel ratio was selected as the vital control parameter.
► After tuning, NOx was reduced from 18 to 2.2 ppm at base load with stable combustion.