The Optimization And Design Of Supercritical Boiler System

This article aims to discuss the role of the boiler economizer and the optimization of heating surface at the end of boiler.First this paper introduces the present situation of our country's energy and the development of thermal power units at home and abroad.By using the unit consumption analysis method,making the unit consumption analysis for different pressure parameters of thermal power unit.Illustrating the the second law efficiency of boiler unit along with the change of unit parameters,and the role and limitations of economizer in the supercritical and ultra supercritical units.Removing the economizer is put forward and adding an air preheater in the place of economizer.Increasing the air absorption of heat to improve the air temperature,and making feed water heat be heated in the chamber of a stove or furnace.Making heat balance calculation for the new structure,and estimating the area of new air preheater and variation of the furnace heating surface.By comparing we can found that the second law efficiency increase with the improve of thermal power unit parameters.Economizer temperature range is not obvious in the high parameter thermal power unit,and the second law efficiency of economizer is the lowest in all of the heating surface.Because of the rise of temperature that is sent into chamber of a stove or furnace,it makes furnace heated area increase.Although new air preheater and the change of heated area will increase the consumption of material,the wall of economizer is thick and consuming a large amount of steel.In the aspect of the total material,through a simple estimate we can find that material quantity of economizer is more than the material quantity of new air preheater and new heating surface.Because of this,the the total consumption reduced.At the same time,removing the economizer is beneficial to boiler system pressure drop decreases,and reduce the rate of electricity.In addition,Increase the air absorption of heat making the air increase temperature,especially the secondary air temperature increased significantly.This change is good for stable combustion and enhancing the ability of thermal power unit to adapt to a variety of types of coal.