Optimization Research On Boiler And Turbine Design Of An 1350MW Double Reheat Ultra Supercritical Unit

Development of supercritical and ultra-supercritical units is the inevitable choice of China's current development of clean coal technology, and the double-reheated technology is an important direction of ultra-supercritical power generation technology, it is an effective way to improve the thermal efficiency of thermal power units. At present, 660 MW and 1000 MW double reheat units have been put into operation, China achieved a breakthrough on the double reheat unit technology, which marked the coming of age of the double reheat. However, compared to the traditional single reheat technology, double reheat is not mature and stable enough because of the short development time. Therefore, the further study of large capacity and high parameters double reheat units to guide us to the further design optimization is of great significance.This paper is mainly for the optimization of the main design parameters for the 1350 MW ultra-supercritical double reheat unit. Models of 1350 MW ultra supercritical double reheat are built to calculate the effects of different feed water temperature to bolier, turbine and thermal system. The calculation shows that:for the unit, in terms of the steam cycle efficiency of the unit, the 1st and the 2 nd reheating surface layout, the heat coordination of milling system and air preheater and SCR denitration plant efficiency, the optimal feed water temperature of the unit is 325 ?.Then, the optimize research of heating surface arrangement of an 1350 MW double reheat boiler is based on the principle of thermal equilibrium. Entirely modeled on a single reheat boiler's heating surface arrangement to design an double reheat boiler, calculation result shows that: the two boilers are different in the proportion of evaporation heat, and then putting forward three measures and response methods to an double reheat boiler. finally,finish the check calculation of the boiler, analyzeing it's varying load and varying coal characteristics.Schemes of 4 different steam turbine type are built to simulate and caculate to research the influence of shaft arrangements and shaft speed celections on efficiency and economy of the 1350 MW ultra-supercritical doubleb reheat unit. By comparing the size of the main equipment, steam parameters of different designs, economic efficiency, as well as project investment of the four different designs, the result shows that: choose a tandem compound 4 flows steam turbine as the best design considering the costs and the efficiency as well as the long-term benefits of the project;when you are considering the cost of the initial investment project, a cross compound 6 flows steam turbine design is the best choice; however, the tandem compound 6 flows steam turbine design and the cross compound 4 flows steam turbine design are eliminated due to the huge investment or technical limitations.