基于煤粉预气化强稳燃的快速调峰燃烧器5 MW中试研究

5 MW pilot test study of rapid peaking burner based on pre-gasificationstrong stable combustion of pulverized coal

煤粉预气化强稳燃技术能够兼顾稳定燃烧与NO_(x)排放控制。基于此,开发了服务于电站锅炉灵活调峰的快速调峰燃烧器,并依托5 MW燃烧试验平台进行热态中试试验,对比不同负荷下的运行性能,研究燃烧器的极限稳燃负荷与快速变负荷能力。结果表明:煤粉进入燃烧器所带有的小型预气化室后发生气化反应,转化为高温燃气和炽热碳粒所组成的预热燃料。在低负荷下,预热燃料进入炉膛后将迅速燃烧,形成根部高温区,保证炉膛稳燃。随着负荷升高,预气化室内气化反应更加充分,配合回流烟气形成良好还原性气氛,实现有效降氮。在无辅助手段条件下,满负荷工况NO_(x)排放为159 mg/m^(3)(6%O_(2)),飞灰含碳率为3.4%,折算燃烧效率99.71%。在9%超低负荷下,快速调峰燃烧器仍能维持炉膛稳定燃烧,在1 h以上长时间连续运行过程中,出口氧量保持稳定。在15%~100%负荷分别用时8和9 min完成快速降负荷与升负荷过程,降、升负荷速率分别可达10.63%/min与9.44%/min。变负荷过程中炉内燃烧保持稳定,且温度分布对负荷变化的响应速度较快,验证了该燃烧器在快速调峰过程中的出色性能。

The strong stable combustion technology of pulverized coal pre-gasification can balance stable combustion and NO_(x)emission control.Based on this principle,a rapid peaking burner for flexible peaking of power plant boilers had been developed,and the operation performance under different loads,the minimum stable combustion load and rapid load variation capacity of the burner were studied on a 5 MW combustion test rig.The results showed that,after entering the small pre-gasification chamber attached to the burner,the pulverized coal would undergo gasification reaction and transform into preheated fuel composed of high temperature gas and hot carbon particles.Under low load,the preheated fuel would burn rapidly after entering the furnace,forming a high temperature zone at the root to ensure the steady combustion of the furnace.With the increase of load,the gasification reaction in the pre-gasification chamber was more complete,and reducing atmosphere was formed with the return flue gas to achieve effective nitrogen reduction.The NO_(x)emission at full load was 159 mg/m^(3)(6%O_(2))without any auxiliary means,and the carbon content of fly ash was 3.4%,meaning combustion efficiency was 99.71%.The rapid peaking burner could still maintain the stable combustion of the furnace under the ultra-low load of 9%,and the outlet oxygen remains stable during the long-term continuous operation of more than one hour.In the range of 15%to 100%load,the rapid load reduction and load rise processes were completed in 8 min and 9 min,and the load ramp rates reached 10.63%/min and 9.44%/min respectively.During the process of load change,the combustion in the furnace remained stable,and the temperature distribution had a fast response to the load change,which verified the excellent performance of the burner in the process of rapid peak regulating.