【摘 要】
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To improve the ignition behavior and to reduce the high NOx emissions of blended pulverized fuels (PF) of semicoke (SC),large-scale experiments were conducted in a 300 kW fired fumace at various nozzle settings,i.e.,ratios (denoted by hf/b) of the height
【机 构】
：
School of Energy Science and Engineering,Harbin Institute of Technology,Harbin 150001,China
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To improve the ignition behavior and to reduce the high NOx emissions of blended pulverized fuels (PF) of semicoke (SC),large-scale experiments were conducted in a 300 kW fired fumace at various nozzle settings,i.e.,ratios (denoted by hf/b) of the height of the rectangular burner nozzle to its width of 1.65,2.32,and 3.22.The combustion tests indicate that the flame stability,ignition performance,and fuel burnout ratio were significantly improved at a nozzle setting of hf/b =2.32.The smaller h(b delayed ignition and caused the flame to concentrate excessively on the axis of the furnace,while the larger hf/b easily caused the deflection of the pulverized coal flame,and a high-temperature flame zone emerged close to the furnace wall.NOx emissions at the outlet of the primary zone decreased from 447 to 354 mg/m3 (O2 =6％),and the ignition distance decreased from 420 to 246 mm when the hf/b varied from 1.65 to 3.22.Furthermore,the ratio(denoted by SR/Sc) of the strong reduction zone area to the combustion reaction zone area was defined experimentally by the CO concentration to evaluate the reduction zone.The SR/Sc rose monotonously,but its restraining effects on NOx formation decreased as hf/b increased.The results suggested that in a test furnace,regulating the nozzle h～b conditions sharply reduces NOx emissions and improves the combustion efficiency of SC blends possessing an appropriate jet rigidity.
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