Responding to the urgent needs of clean and efficient utilization of coal under the background of national"carbon peaking and carbon neutrality",the pulverized coal preheating combustion technology has been developed in industrial boilers,power plant boilers and other fields.In this technology,pulverized coal is modified at high temperature in a fluidized preheating burner,then the preheated fuel enters the furnace for graded air distribution combustion,thus high efficiency and low NOx combustion of pulverized coal is realized.Moreover,technical verification was carried out on a 60 t/h pulverized coal boiler,which adopts two preheating burners with side wall hedge arrangement,and one preheating burner is designed with thermal power of 26 MW.Using bituminous coal as raw material,the operation and NOx emission properties of the boiler at 10％～100％operating loads were studied experimentally,and the results showed that,the boiler operated stably and well at each load,it achieved stable operation of 10％ultra-low load without any auxiliary means.The preheating burners had reasonable operating parameters and stable circulation state,which can meet the requirements of wide load operation of the boiler.The combustion efficiency of the boiler at each operating load were all above 97％,the thermal efficiency of the boiler were above 85％at 10％and 20％operating load,and above 90％at 30％and above operating load.By adjusting the air distribution,the original NOx mass emission of the boiler at each operating load can be controlled lower than 50 mg/m3(φ(O2)=9％).The successful demonstration of the 60 t/h pulverized coal preheating combustion boiler provides important support for the development and application of clean,efficient and flexible combustion technology of pulverized coal.
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