Numerical Simulation Of Coal Combustion Optimization For A600MW Supercritical Pressure Boiler

The dominant position of coal in China’s energy structure will not change over a longer period of time, to improve the energy efficiency of coal combustion and reduce pollution is one of the current focus problem.Supercritical boilers have the ability to solve these problems, and it is widely used in coal-fired power plants.This article study a supercritical boiler,ane use FLUENT to simulate the boiler on different conditions, determine the optimal parameters in order to achieve combustion optimization purposes.Model Carrier in this paper is a power plant supercritical boiler,the boiler’s model is DG2090/25.4-Ⅱ7, and the paper relys on numerical simulation software to simulate each process in the furnace.Calculating gas-solid two phases use the RNG turbulence model;For the coal particles volatiles releaing,we use the competing reaction model;for the gas phase turbulent combustion,we use the mixture fraction-probability density function model;for the coke combustion we use motion/diffusion controlled combustion model; for the radiation heat transfer for furnace,we use P-1radiation model;for coal particle trajectory,we use stochastic particle trajectory model; finally,the paper introduce the coupling between discrete and continuous phase calculation model.First, the paper stimulate the boiler100%BMCR conditions of the boiler,and detailed discuss the furnace velocity field, temperature field, the oxygen concentration distribution and NO concentration distribution,conclue the front wall of the boiler combustion characteristics,and Theoretically prove the accuracy of the simulation results,The results show furnace exit temperature and the concentration of NO emissions in line with the boiler’s actual operating,therefor,the simulation results can prove a more complete reflection of the actual operation, which can be in-depth study of the variable conditions. Secondly, the paper varys the intensity of the cyclone swirling secondary air, excess air ratio and burn air damper rates, analyzes the effects of these parameters foe the safe operation of boilers, combustion efficiency and NO emissions, then result a reasonable parameters,and provided a refernce for boiler safety operation.