Application And Performance Analysis Of Energy Saving And Efficiency Improving Retrofit Scheme For Datang Dangtu 660MW Supercritical Steam Turbine Unit

As the world’s largest carbon emitter,China has committed to the world that its carbon dioxide emissions will reach the peak by 2030 and achieve carbon neutrality by 2060.For the existing units,it is necessary to further reduce the heat consumption of steam turbine and improve the operation efficiency of steam turbine in order to meet the requirements of reducing carbon emissions.This paper takes the 660 MW supercritical unit of Dangtu Power Generation Co.,Ltd.as the research object,from the aspects of steam turbine body,feed pump steam turbine and thermal system,combs the problems of the unit before the transformation,and makes a comprehensive analysis of these problems.According to the results of the problem analysis,the research and analysis of the steam turbine body transformation scheme,the feed pump steam turbine transformation scheme and the thermal system upgrading scheme are carried out one by one,and the appropriate and effective comprehensive energy-saving and efficiency improvement transformation scheme is selected.For the steam turbine body transformation scheme,this paper mainly studies the selected new process and new technology of body transformation,such as multi-stage small enthalpy drop reaction design concept,integral structure design of high and low pressure inner cylinder,pre twisted assembled diaphragm and application of new material steam seal,etc.,and analyzes its effect on energy saving and efficiency improvement.According to the calculation and comparative analysis of design thermal parameters before and after the unit transformation,the same results are obtained The calculation and comparative analysis of the thermodynamic parameters of the design of the retrofit scheme of the same type of units in the same period are selected to test the design effect of the retrofit scheme of the steam turbine body,and the corresponding analysis opinions on the design scheme are put forward according to the analysis of the design parameters.For the retrofit of the feed water pump steam turbine,this paper mainly makes a comparative study on the technical parameters of several main domestic feed water pump steam turbine manufacturers Through the analysis,and then select the most suitable model for transformation,in order to maximize the energy saving and consumption reduction and the actual needs of the site.In addition,for the the thermal system,considering the domestic mainstream design experience,the thermal system upgrading scheme is analyzed from the perspective of improving the feed water temperature and the thermal system economy.In order to fully understand the practical application effect of this energy-saving and efficiency improvement project,this paper analyzes the performance based on the high-precision performance test after the transformation,and compares the cylinder efficiency,heat consumption and other key indicators with the actual performance data before the transformation and the design value data of the transformation scheme.The results show that:the cylinder efficiency and heat consumption are significantly improved compared with those before the implementation of the scheme,and the results basically meet the design requirements which the cylinder efficiency of high,medium and low pressure cylinders are88%,93% and 89% respectively under THA condition(3VWO condition),and the design heat consumption is 7585 k J/k Wh.And this proves that the implementation of the energy saving and efficiency improvement scheme has played a significant effect.In addition,by comparing the two performance tests with a span of 20 months,this paper analyzes and studies the performance deterioration trend of the steam turbine unit after the implementation of the transformation scheme,so as to further test the rationality of the application of the energy saving and efficiency improvement scheme.Finally,this paper analyzes and studies the actual problems in operation after the transformation,and puts forward improvement measures,so as to provide reference for the determination of the transformation scheme of the same type of units and the design adjustment of the manufacturing unit.