Influence of nozzle height to width ratio on ignition and NOx emission characteristics of semicoke/bituminous coal blends in a 300 kW pulverized coal-fired furnace  

作　　者：Liutao SUN Yonghong YAN Rui SUN Zhengkang PENG Chunli XING Jiangquan WU 

机构地区：[1]School of Energy Science and Engineering,Harbin Institute of Technology,Harbin 150001,China

出　　处：《Frontiers in Energy》2021年第2期431-448,共18页能源前沿（英文版）

基　　金：This work was supported by the National Key Research and Development Program of China(No.2017YFB0602002);National Natural Science Foundation of China(Grant No.51536002).

摘　　要：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 furnace 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 hf/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 hf/b conditions sharply reduces NOx emissions and improves the combustion efficiency of SC blends possessing an appropriate jet rigidity.

关 键 词：rectangular jet burner nozzle height to width ratio ignition characteristics pyrolyzed semicoke(SC)and bituminous blend NOx formation 

分 类 号：TK16[动力工程及工程热物理—热能工程]