Modification Of Steam Seal And Optimization Of Flow Passage Clearance For Steam Turbine Of 630MW Supercritical Unit

Thermal power generation is the main electical power in China,and the operating efficiency of the unit has a significant impact on China's energy conservation and emission reduction strategy.As one of the key equipments in the process of thermal power generation,the operation efficiency and security of steam turbine plays great role in the economics in China.This paper focuses on the current technical reform implementation of the thermal power enterprises by flow gap reform optimization and puts forward a way to improve the efficiency of steam turbine.For a concrete unit,a seal clearance optimization problem is researched and designed,and the reform effect was summarized.Firstly,the basic structure and working principle of the large power plant steam turbine are analyzed.Combined with the operation of steam turbine 2# power units,the unit was significantly higher than the design value of the unit efficiency and heat consumptionsince its operation.The safeguard measures technical scheme of steam turbine circulation part of the reform and the implementation process is given to seal retrofit and optimization gap.On the basis of the analysis of the performance test of the unit,the steam seal reformation and the clearance clearance optimization project are carried out.In order to reduce the heat consumption of steam turbine,reduce leakage loss maximum,based on understanding of the same type of unit renovation work and communications with the manufacture,and according to the unit operating parameters,a new optimal radial clearance is proposed according to the seal structure,material,and different positions,which is less than the design standards about 0.05mm-0.15 mm.Through the repair of each steam seal teeth,all the flow parts were shot blasting descaling treatment,improve the sealing effect,and reduce the amount of steam leakage.In order to ensure the sealing gap adjustment accuracy and reduce measurement error on steam turbine rotor center,separator / steam seal body socket center to adjust the quality of the seal clearance,by measuring each level according to the rotor sagging amount of different correction.The performance test of steam turbine unit show that the implementation of reconstruction and optimization gap has gained the goals.The heat consumption of steam turbine is 7585.8kJ/kWh,and the power supply coal consumption is 297.59g/kWh,which is reduced by 10.32g/kWh than that before reform.According to the annual generating capacity of 3.9 billion kWh,40000 tons of standard coal can be saved.In the normal load range from 300 MW to 600 MW,the vibration amplitude of #1 and #2 bearing bush of steam turbine was excellent with less than 80?m.