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Currently tangentially fired boiler of power plant is the most widely used and most mature furnace, which accounts for 80% of total installed capacity. Because of the variability of burning coal, often unstable combustion, ultra-mild coking and other issues, the safety of the boiler and economy caused a great impact. Through traditional thermal test methods, not only consumes a lot of manpower, material and financial resources, and most are by virtue of past experience for debugging, there is a certain blindness. However, by numerical simulation method can predict the furnace pulverized coal combustion process for the safe operation of the boiler to provide evidence. This article will fight to the cold gray area between the part of the screen as the computational domain. For Tangentially Fired characteristics, the main combustion zone method using Paving meshing direction and speed of the grid to ensure consistency of the direction, minimizing the false diffusion. In the calculation process, by adding after the superheater separate screen and screen flow and heat transfer considering its impact, and according to the actual operating parameters of the model for a reasonable set so that the results more realistic. Author Yuncheng in Shanxi Datang Power Plant 2080t / h tangentially fired boiler for the study, the use of numerical simulation method to analyze the working conditions in the original furnace aerodynamic field, temperature field distribution. With tangentially fired thermal characteristics and comparison of calculation results prove meshing methods used, the physical model, parameter settings, etc. is more reasonable. On this basis, we study the boiler excess air ratio, load and air distribution methods changed, the furnace aerodynamic field, temperature field and other effects, has been a series of useful results. Numerical simulation results show that with the increase of excess air ratio, furnace flame center down the main combustion zone temperature rises, the furnace flue gas outlet speed, average furnace exit gas temperature decrease and increase the amount of oxygen furnace , NOx generated in volume. When the boiler load increases, the main combustion zone airflow significantly faster, move to the sides of the furnace flame center, NOx generation volumes. When changing the secondary air G and eliminate cyclone wind speed, the furnace excess air ratio rose to 1.22 from 1.2, the furnace flame center down, reducing the residual rotational momentum. The results of the simulations used to guide the actual operation of the boiler, the results collected at the scene confirmed that the change in the G and eliminate secondary air cyclone, the left and right side of a desuperheater water ratio decreased from 2.85 to 2.55, separated platen superheater is reduced from four to two points over-temperature, temperature and amount of water from 150.7t / h reduced to 105.9t / h, boiler safety and economy have been improved. Practice has proved that numerical simulation method for guiding the boiler combustion adjustment is an effective method.
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