Study On Optimal Management Of Start-Up And Shutdown Process Of Large Siemens Combined Cycle Generator Unit

At present,domestic large gas-steam combined cycle units are using imported technology.F class Gas-Steam Combined Cycle Units in China mainly use double shift(start in morning and stop in evening)to participate in peak load,but it mainly operate in base load and few participate in peak load abroad,there is wide difference between both operation mode.This paper will combine with the operation instance of three Xiaoshan SGT5-4000 F Gas-steam combined cycle units,regarding to the operation mode of frequent start-stop and peak load in China and the three important evaluation indicators of operation economy,environmental protection and safety in power plant,research the problems and deficiencies.During the start and stop periods,due to the fast speed,the unit needs to operate in low load and low efficiency area waiting for steam heating,pressure boosting and ST inlet warm-up,and it will affect the economic efficiency of the unit.For stabilize combustion,GT almost operates in diffusion combustion mode during start-stop low load area,but it will lead to high NOx production and affect the environmental protection.Frequent start and stop of the unit will cause the thermal system to experience heat expansion and cold contraction over and over again,the rotor of ST to bear great alternating stress,and it poses a threat to the unit safety and rotor life.In addition,heavy operation work in Start-stop stage also will affect the unit safety.This paper will use SWOT analysis method,PDCA Deming ring quality management method,7S quality management method etc comprehensively,carry out a series of researches of start-stop optimization of large SIEMENS Combined Cycle Units,mainly including:(1)The research of raising Start-stop economy of unit.According to the "barrel effect" management idea.Analyzing the data of the whole start-stop process,it is crucial to shorten the waiting time for qualified steam and the time to warm up the steam turbine at low speed during the cold starting process of the unit,and shorten the waiting time of heating tube during the hot start process.By identifying "weak spots",this paper works out optimization measures to improve the start-up speed and the comprehensive economy as far as possible.(2)The research of raising environmental performance in the Start-stop phase.The hour mean value of NOx will exceed the standard in the Start-stop phase,we adopted PDCA Deming ring quality management method,carried out technical innovation of GT inlet humidification to control the humidity and temperature of GT inlet humidification accurately,and it will reduce NOx emission and solve the difficult environmental problems effectively.(3)The research of raising Start-stop safety of unit.Through on-line early-warning analysis system,ensure the equipment anomaly and fault can be alarmed in advance,and we can take preventive measures in time to increase the safety and reliability of equipment.Under the lean team construction based on 7S management,improved the team management,formed a good habit,maintained civilized production to promote the safe operation of enterprise.