Combustion Simulation And Operation Optimization Of Natural Circulation Drum Boiler

When the combustion is preformed in boiler,the internal chemical reaction process is very complicated.For the actual operation of the boiler,there are many limitations in hot state experiments,such as heavy workload,complex conditions,difficulty of measurement,so that the numerical simulation has been widely used for the domestic and foreign researchers.In this paper,the numerical simulation of the high pressure natural circulation drum boiler in a power plant is carried out,and the aerodynamic field,temperature field,flue gas component concentration,NOx concentration and coal particle trajectory are analyzed.Then the boiler operating conditions are simulated and analyzed,and the optimal operating conditions are summarized.It is of great significance for the engineering application,and hence the realization of the goal of building a resource-saving and environment-friendly society.The area of the combustor is divided into four kinds of unstructured grids by pave,and the other parts of the furnace are divided into quadrilateral structured grids by Map.By using the combustion simulation of boiler under different conditions of the commercial CFD software,we analyze of the aerodynamic field in furnace,temperature field,flue gas concentration,NOx concentration and coal particle trajectories,and in this paper the rationality of the mesh and the selection of mathematical model is verified.The results show that,in the original condition of the boiler combustion,four corner tangential gas flow in the furnace is good,and along the furnace height direction spiral,good aerodynamic field in the furnace is found,where high temperature mainly concentrated in the burner region,and O2 and CO are mainly distributed in the burner region.The highest CO2 concentration locates in the furnace outlet,while the high temperature region NOx mainly concentrated in the furnace,and the nozzle of the coal burnout rate is good.When the incident angle is small,the rigidity of air flow in the furnace is strong,and the furnace flame center position is elevated,the air flow is not good,the furnace temperature is low,the coal burnout rate is low;When the incident angle is large,such flow is disorder,and easy to flush the water wall,high NOx emissions,therefore we suggest that the incident angle is 2 degrees to 5 degrees.The top two wind speed,aerodynamic field in the furnace,the furnace is located in the center position of the flame burner,the coal burnout rate is high,and hence the high NOx emissions.For the top two wind,tangential gas in the furnace is formed from the center of the flue gas,is easy to flush the water wall,and the flame center location elevation the coal burnout rate is low,and NOx emission is low.With comprehensive consideration,the top two wind can be added to the 49m/s.This study provides a reliable basis for the implementation of the boiler thermal performance experiment,and provides an important reference value for how to change the angle of incidence,to optimize the distribution of wind and predict the generation of NOx in the combustion process of the boiler.