Analysis And Optimization Of Two Reheat System Of Ultra Supercritical 1000MW Boiler

With the rapid development of our country's electric power industry,the development of thermal power units shows a significant high-caapcity and high-parameter trend.Till the end of 2016,nearly 32% of the total installed capacity of thermal power units are 1000 MW units.The operation quality of this part of the unit has a very important impact on the the entire grid operation reliabilty and economic efficiency.Besides,the global energy crisis and environmental problem become increasingly prominent,the secondary reheat technology,with the advantage of large capacity,high parameters,high efficiency and low emissions,wil become the direction for future thermal power dvelopment.Based on this background,this paper takes the Guodian Taizhou ultra supercritical 1000 MW secondary reheating boiler project as the research object to analyze the thermal unit heating system and the heating surface of the boiler.Through the optimization design of the heating surface structure,the power generation efficiency can be improved and the structural damage accident during operation can be reduced.This paper uses GateCycle sofeware for modeling the heating system of reheating unit and analyzing the heating system structure of the unit.This paper uses ANSYS software for making fem stimulative analysis of the residual stressed produced by the water wall tube in boiler heating structure and reducing the bursting of water wall tube in operation.It also uses ANSYS to make numerical stimulation of water wall temperature distribution and thermal stress.The situation of the numerical stimualation is based on the set of thermal boundary condition with the converctive heat transfer in the tube and the outer heat flux density and the elastic mechanical boundary condition as the tube pressure and corresponding displacement constraint.With the numerical stimulation,the way for improving the force of pipe screen has been proposed.