燃用神华煤600MW机组超低NOx燃烧技术研究与工程实践

发布时间：2018-03-05 03:21

本文选题：锅炉　切入点：空气分级　出处：《华北电力大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：在日益严格的环保标准下,火力发电厂采用新技术来降低NOx的排放已迫在眉睫。结合某电厂#3机组的实际特点,在双尺度低NOx燃烧技术基础上,通过在主燃区中引入节点功能区,运用贴壁技术和浓淡煤粉燃烧器,将相邻的2层一次风喷口的下层改为为上浓下淡煤粉喷口,将上层改为下浓上淡煤粉喷口,并且设置一次风与2层一次风喷口之间的二次风小角度偏置,同时将贴壁风布置在在中间二次风两侧、优化主燃烧器区的过量空气系数为0.75~0.80、压缩主燃区高度1860mm、增加7层分离燃尽风喷口,使其分配35%~40%的SOFA燃尽风量,形成高达10m的超大的还原区等优化设计方案、过程中实现精密的安装质量控制、以及通过制粉系统和辅助风系统等热态综合调试和优化,启动后锅炉实现了结渣程度明显减轻、燃烧高效安全、炉膛出口NOx排放浓度大辐降低的良好效果,并借助调试后获得的锅炉燃烧特性曲线固化至DCS自动控制系统中,通过DCS自动和运行人员根据煤种、环境温度等实际条件微调相结合的方式,实现了机组长周期、安全、稳定运行。通过技术研究与工程实践,该电厂3号炉的机组负荷在50%~100%的范围内,都能实现SCR入口处的NOx排放浓度在100mg/Nm~3左右;在550MW左右的机组负荷,NOx排放最低甚至可达到90 mg/Nm~3左右的水平,达到国际领先水平,同时锅炉效率没有明显变化,机组的安全可靠性可以保证,实现了纯神华煤连续满负荷运行,实现了预期的目标。
[Abstract]:Under the increasingly stringent environmental protection standards, it is extremely urgent for thermal power plants to adopt new technologies to reduce NOx emissions. Considering the actual characteristics of #3 units in a power plant, based on the dual-scale low NOx combustion technology, By introducing the node function zone into the main combustion zone, using the wall sticking technique and the thickening pulverized coal burner, the lower layer of the adjacent primary air nozzle is changed to the upper thick and the lower light pulverized coal jet, and the upper layer is changed to the lower concentration and the lower light pulverized coal jet. At the same time, the secondary air between the primary air and the secondary air nozzle on the second floor is biased at a small angle, and the wall adhering air is arranged on both sides of the middle secondary air. The excess air coefficient of the main burner is 0.75 ~ 0.80, the height of the compression main combustion zone is 1860 mm, and the seven separate exhaust air vents are added to distribute 35% of the SOFA exhausted air volume and form a super large reduction zone of 10 m. In the process, the precision installation quality control is realized, and through the comprehensive debugging and optimization of the pulverizing system and the auxiliary air system, the slagging degree of the boiler after startup is obviously reduced, and the combustion is efficient and safe. The good effect of decreasing NOx emission concentration at furnace outlet is good, and the combustion characteristic curve of boiler obtained after debugging is solidified into DCS automatic control system. Through DCS automatic and operation personnel according to the coal type, the combustion characteristic curve of boiler is solidified into the DCS automatic control system. The long period, safe and stable operation of the unit has been realized by combining the environmental temperature and other practical conditions with fine adjustment. Through technical research and engineering practice, the unit load of the No. 3 boiler in the power plant is in the range of 50% or 100%. Both of them can realize that the NOx emission concentration at the entrance of SCR is about 100mg / Nmm3, and that the lowest or even the lowest emission of NOx at the 550MW unit can reach the level of 90 mg/Nm~3 or so, reaching the international leading level, while the boiler efficiency has not changed obviously. The safety and reliability of the unit can be guaranteed, realizing the continuous full load operation of pure Shenhua coal, and achieving the expected goal.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621;X773

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