Calculation And Analysis Of SCR Reactor Structure Of Coal-fired Generator Unit

Coal resources are relatively abundant in China's energy composition,which leads to coal-fired power generation as the main source of power production and supply in China.With the development of society and technology,in 2011,the government has passed stringent environmental regulations,requiring that the emission concentration of nitrogen oxides from all thermal power units should not exceed 100 mg/m3 from 2014.Nitrogen oxides(NO_X)are one of the main sources of atmospheric pollution in coal-fired power generation process.The SCR(Selective Catalytic Reduction)process is a more general way of denitrification(denitrification of nitrogen oxides)for coal-fired generating units,and SCR reactor is the central equipment in denitrification process.Its main function is to support catalyst and provide space for denitrification reaction.At present,SCR reactor has basically become the necessary equipment for new coal-fired generating units.And in recent years,it has been widely used in industrial fields such as steel plants,cement plants and so on.However,there is no unified design idea and relevant design standard for such equipment.Therefore,it is necessary to study and discuss the structure calculation and analysis of SCR reactor.In this paper,the structural design methods and calculation forms of SCR reactor are compared and analyzed.The main research contents are as follows:(1)To determine the material characteristics.Because the working temperature of SCR reactor is as high as 400 ? and the maximum transient temperature can reach 450 ?,the structural material of SCR reactor is generally Q345 B steel considering cost factors.The allowable stress of Q345 B steel is much lower at 400 ?,however,the design values of material properties at this temperature in the relevant standards and specifications are not consistent.The input values of material properties suitable for engineering design and calculation are determined by sorting out the codes and standards.(2)Theoretical calculation and analysis of reactor wall and rib.Usually,this thin-walled shell structure does not consider bearing in-plane loads in engineering calculation.For example,in the relevant standard codes such as Code for Design of Pipeline with Bituminous Air and Pulverized Coal,only the pressure inside the pressure vessel and some uniform loads are considered,the direction of load is perpendicular to the plate.The theoretical calculation results are great different from that calculated by the finite element analysis software.In this paper,the stiffness distribution of stiffened structure of reactor equipment wall plate is analyzed theoretically,and compared with the calculation structure of finite element analysis software,so that a safe and economical design method can be obtained.(3)Finite element analysis of plate stiffeners.PROSTAAD,a software highly applied in the electric power industry,is a general finite element structural analysis software for engineering.It can analyze and calculate steel structures by choosing different standard methods,and give detailed analysis results.However,because there is no widely applicable standard specification for plate analysis,it can only let the plate participate in the whole process.The results of stress calculation on the plate are provided after the stiffness distribution of the body.Therefore,in addition to the finite element analysis of SCR reactor structure by PROSTAAD,the finite element analysis software MIDAS is used for calculation and analysis,and two CAE analysis results are compared with the previous theoretical calculation results to determine the reliability of the theoretical analysis method.