600MW Sub-critical Steam Turbine Brush Seal Transformation And Application Research

A 600 MW sub-critical steam turbine of a power plant is designed and manufactured by Harbin Steam Turbine Plant Limited Company on the basis of Westinghouse technology.It is a sub-critical,primary intermediate reheat,reactor-based,four-cylinder,four-exhaust and condensing 600 MW steam turbine.The model is N600-16.7/538/538.Under rated parameters,the main steam is designed.The steam flow rate is 1772.77t/h and the heat consumption rate is 7783.4KJ/ kW·h.According to the performance test of steam turbine of # 1 unit,it is found that when the generator power and inlet temperature are equal to the design value,the extraction pressure and extraction temperature of each stage of high and medium pressure cylinder deviate from the design value,the steam expansion work of each stage of high and medium pressure cylinder is insufficient or there is leakage between stages before these extraction stages.The unit has poor economy and high steam consumption rate.Aiming at the reasons that the cylinder efficiency of steam turbine is lower than the design value,the extraction parameters are higher than the design value,and the expansion of steam in the cylinder is insufficient,it is determined that the current solution is to rationally adjust the seal clearance,and carry out the seal transformation to realize the long-term planning for the steam turbine through-flow transformation.In this paper,the main steam seal types,such as honeycomb,Braden and contact type,which are commonly used in engineering practice,are investigated,their basic principles,advantages and disadvantages are analyzed,and the economic and technical comparison is made.At the same time,through investigating the effect of engineering renovation of brother power plant and drawing lessons from the renovation,it is concluded that the brush seal is flexible and can be self-adapted to the shaft.Instantaneous jump,quick return to the original state,maintain the original clearance,will not be like the traditional hard seal due to the unit over-critical or abnormal vibration caused by clearance permanent bigger,will not scratch the rotor,will not increase the vibration of the unit,can be very good to maintain the safety of the unit;brush seal clearance than the original hard tooth is smaller,can reduce steam leakage And improve the efficiency of the unit.The reform plan of turbine brush type steam seal is decided.According to the analysis of performance test parameters after retrofitting,the coal consumption of generating unit is reduced by 1.01gce/kWh and the coal consumption of power supply is reduced by 1.13gce/kWh at 100% rated load.According to the calculation of annual generating capacity of 3 billion kWh,the annual income is about 2.727 million yuan,which has obvious energy-saving efficiency.Fruit.The engineering practice shows that the brush seal,as a kind of flexible seal to replace the traditional labyrinth seal,has incomparable advantages,and can provide reference for the same industry units.