Numerical Simulation And Experimental Research On The 300MW Boiler Burner Of Hanchuan Power Station

In recent years, with the application of dense-dilute technology in straight-flow burners, it can do better in firing of pulverized coal and decreasing the emission of NOx. The boiler designers developed horizontal dense-dilute burners based on vertical dense-dilute burners. The application of horizontal dense-dilute technology in some boilers has resolved many problems, such as the fire, self-supporting burning and burn-up problem of low volatile coal. At the same time, the technology has enhanced the ability of peaking and reduced fuel oil at low load. In view of improving the flame stability in low load, a retrofit of the 300MW boiler coal burner is carried out in Hanchuan Power Station.The paper simulates the gas phase flow field, particle track and concentration distribution in the coal burner and concentrator of the 300MW boiler in Hanchuan power plant by the software of FLUENT CFD. estimates the erosion state and optimizes the design plan of the burner to the concentrator was also estimated.Under the condition that the configuration of the burner was changed and other operating parameters stay the same, the simulation analysis to the gas phase and solid phase was carried out. Results showed that the bluff-body and blades had large influences on the exit airflow velocity of the fuel-rich side while little on the fuel-lean side. To both the rich side and lean side exit, the high speed area is concentrated on the middle area while the axial velocity decreases gradually from the middle area to the periphery. At the exit of the bluff-body, recirculation area is formed because of the negative downstream axial velocity. In the simulation of the gas-solid phase, because of the introduction of the particle phase, the ratio of the fuel- rich stream and fuel- rich stream at the exit of the burner is approaching to 1, which shows that particle phase has significantly affected the ratio of the fuel-rich and lean-fuel stream. On both sides of the bluff-body there exists high concentration and the airflow impact the bluff-body with a certain angle, which causes severe erosion of the two sides of the bluff-body. Bluff body and blades have large influences on the concentration ratio of burner, so effective measures should be taken to extend the life of the bluff-body and blades.The concentrator with four blades has an ideal Fuel-rich-to-fuel-lean air ratio and ahigh concentrating ratio, therefore is beneficial to the performance of the burner. It is suggested that four blades are of the first choice for the concentrator.Through combustion debugging test of the No. 3 boiler in Hanchuan power plant for enhancing ability in low load operation. The paper analyzes the relationship between load and NOx emission and put forward some suggestions for optimizing operation at low load.