Abstract: To solve the problems such as low thermal efficiency, high NOx emission and slag bonding in a 150 t/h pulverized coal boiler, A new idea was proposed to use enriched-oxygen air as the over flame air and welted edge air. Using k-e- -g turbulence combustion model for computation of the gas phase and two competing reactions for coal devolatilization, the flow and temperature fields and NOx emission in the boiler were simulated. After the oxygen-enriched combustion technology was used, the boiler combustion efficiency was above 96% and the efficiency over 91.40%, the NOx emission was 625~763 mg/m3, the slagging phenomenon did not occur on the furnace water-cooled wall and superheater.

Key words: pulverized coal boiler, local oxygen-enrichment combustion-supporting technology, numerical simulation, NOx

摘要： 针对某公司150 t/h煤粉锅炉燃烧效率低、NOx排放浓度高、炉膛结焦等问题，提出了用富氧风作为炉顶燃尽风和贴壁风的分级燃烧新思路，采用计算机数值模拟技术和k-e- -g气相湍流燃烧模型及煤双挥发反应热解模型，对锅炉炉内速度场、温度场及燃烧过程中的NOx生成浓度进行数值模拟. 技术改造后锅炉的燃烧效率保持在96%以上，锅炉综合热效率在91.40%以上，NOx排放量为625~763 mg/m3，未发现炉膛水冷壁和高温过热器上有结渣现象.

关键词: 煤粉锅炉, 富氧局部助燃, 数值模拟, 氮氧化物