By taking a 600 MW unit boiler co-firing coal with biomass gas as the research object

the ANSYS software is applied to simulate the effects of biomass gas nozzles positions on temperature distribution

composition distribution and NO_x mass concentration distribution of the boiler

and the influence law of the biomass gas nozzle position on the combustion and NO_x generation in the furnace was obtained. The results show that

the burn-out rate of pulverized coal is little affected by the mixture of biomass gas. Compared with the pure coal combustion condition

the temperature of flue gas at finance outlet and the NO_x mass concentration decreases under the cocombustion condition. Under the studied working conditions

with an increase in the height of biomass gas nozzle

the flue gas temperature at the furnace outlet rises

the NO_x mass concentration decreases at first and then increases

the mass fraction of O_2 and CO in the burner area decreases

and the CO_2 mass fraction rises. The mixed combustion condition in the furnace reaches the best and the NO_x mass concentration at the furnace outlet reaches the lowest when the biomass gas nozzle is located at the primary air nozzle of the second layer.