Research On Wall Temperature And Heat Absorption Deviation Of DG3000t/h Ultra Supercritical Boiler Water Wall

It is difficult to change the situation of coal that is the main energy in China in a short time,while there is a serious waste of coal-fired power generation in China.These factors restrict the development of society.In order to achieve the goal of energy saving and emission reduction,it is necessary to develop effic ient ultra supercritical coal-fired power generation technology.The purpose of this paper is to study the phenomenon of large wall temperature and heat absorption deviation of the upper wall of the super supercritical boiler in Luyang plant under low load.According to the phenomenon,the temperature measurement points was densely arranged on the basis of the original DCS in order to test the temperature under different load,coal quality,air distribution modes and operation modes of coal mills,and then the data statistics and processing will be carried out.Finally,the distrubution of water wall temperature and heat load will be grasped.Then the hydrodynamic calculation will be carried out on the basis of the above tests.The flow network system is used to divide the water wall into a system which is composed of loops and tube segments.In order to calculate the flow distribution,the pressure change along the flow direction,outlet steam temperature,w orking fluid temperature and wall temperature,the mass conservation equation,momentum conservation equation and energy conservation equation will be established on the basis of the flow network system.Finally,the operation characteristics of water wall are evaluated comprehensively,and the methods of improving and optimizing the design are put forward.Finally,the finite element method is used to analyze the thermal stress distribution of the water wall tube in the front wall of the upper furnace.First,the relevant theories of thermodynamics and elastic mechanics are combed,and the corresponding boundary conditions are determined.The thermodynamic boundary condit ions are the convection in the tube and the heat flux outside the tube.The boundary condition of the elastic mechanics is the displacement constraint and the pressure of the working medium in the tube.Second,the temperature distribution,deformation and thermal stress distribution of the two-dimensional water wall section are simulated by using ANSYS Workbench.