Abstract: When the low quality coal is used in a swirl opposed firing boiler,it is difficult to ignite in time and burn out,which causes the temperature of the main combustion zone to be low.The unstable combustion of the furnace will lead to the high temperature corrosion and slagging in the water wall,and the overheating problems on the upper convection heating surface.the carbon content of fly ash is also greatly increased,thus the thermal efficiency of the boiler is significantly reduced.This is a major problem facing the operation of the power plant boilers.For a 1 000 MW opposed firing boiler,the combustion performance and the distribution of the characteristic parameters was studied by numerical simulation method when it was burned inferior coal,and the results were compared with the designed coal,so as to provide some basis for improving the coal adaptability of the boiler.The results show that,compared with the designed coal,the ash content of inferior coal is higher and the calorific value is lower.The classified air distribution mode of the original burner is not conducive ignited in time and maintain the stable combustion,and the fire point is postponed and the temperature distribution of the horizontal section of in the furnace is uneven.The high temperature area appears near the water wall.The large area of high concentration CO generates near the center of the water-cooled walls,and the high temperature zone in the furnace center also decreases for the incomplete combustion and the temperature of the convective heating surface rises up.That is,the flame center is close to the burnout zone,which is easy to cause the high temperature corrosion and slagging in the water-cooled wall,and the overheating of the convective heating surface.The fume temperature and carbon content in fly ash at the outlet also increases,that is,the boiler efficiency will decrease.In addition,due to the irrationality of the staged combustion organization,the production of NOxat the furnace outlet is also significantly increased.In the actual industrial application,the quality of the burning coal should be blent with the designed coal to improve the combustion characteristics of the low quality coal and ensure the combustion stability of the boiler.Also,the original swirl burner should be optimized and reformed,and the mixing of primary air and secondary air should be strengthened in advance,and the primary air velocity is reduced appropriately or the wall wind system is added near the water-cooled wall to ensure pulverized coal ignition in time and improve the ability of the boiler to burn the low quality coal.