Introduction  The gas turbine generator set (GE-PG9351FA) with a DLN2.0 + burner and a designed NO_x emission concentration of 50 mg/m³ is used in a gas turbine power plant. During the warm-up periods, the generator set emitted a large amount of yellow smoke, which violates provisions stipulated in the "Emission Standard for Air Pollutants from Thermal Power Plants" (GB 13223—2011) and is complained by the surrounding residents. According to the new emission regulations for environmental protection in Jiangsu, starting from January 1, 2023, the converted NO_x emission average throughout the operation period should be less than 30 mg/m³. In order to meet this requirement and reduce the emission of yellow nitrate smoke during start-up, the renovated SCR denitration technology for the flue gas of the HRSG (Heat Recovery Steam Generator) is adopted. Data simulation, deduction, analysis and summarization of various indicators are conducted during the start-up process to refine a reasonable startup operation method.

  Method  To validate the feasibility of this method, the power plant conducted multiple peak shaving start-up process operation tests. Based on the actual NO_x emission characteristics, adjustments were made to the start-up point, gas turbine load control, and input nodes for the SCR system in the operation method. This process resulted in an optimized operational strategy.

  Result  The test results show that by optimizing the SCR denitration system input point, gas turbine start-up point and warm-up load after grid connection, the converted NO_x emission average throughout the operation period is less than 30 mg/m³, and the phenomenon of yellow nitrate smoke disappeared.

  Conclusion  This strategy is based on the characteristics of NO_x and yellow nitrate smoke emission during the gas turbine start-up process. Afterward, through data deduction and numerous experiments for validation, it can provide direct guidance for reducing yellow nitrate smoke emission during the start-up process of similar gas turbines. Additionally, it can serve as an analytical reference for controlling NO_x emissions during peak shaving operations in gas turbine power plants.