1000MW塔式锅炉中低负荷下低NO_x排放优化  

NO_x Emission Optimization of a 1 000 MW Tower Boiler During Medium and Low Load Operation

作　　者：汪华剑[1] 赵斯楠 方庆艳[2] 张成[2] 魏铜生[1] 周虹光[1] 陈刚[2] 

机构地区：[1]西安热工研究院有限公司,西安710032 [2]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《动力工程学报》2016年第10期765-772,794,共9页Journal of Chinese Society of Power Engineering

基　　金：华中科技大学校青年基金资助项目(01-18-120070)

摘　　要：针对大型燃煤锅炉在中低负荷下普遍存在的炉膛出口NO_x质量浓度偏高的问题,对某台1 000 MW超超临界塔式锅炉炉内流动、传热、燃烧及污染物排放特性进行了数值模拟研究.通过改变周界风挡板开度及适当降低运行氧体积分数,对该锅炉中低负荷下NO_x质量浓度高的问题进行优化.结果表明:模拟结果与现场试验数据符合得较好;中低负荷下,减小周界风挡板开度,燃烧初期化学当量比减小,炉膛出口的NO_x质量浓度相应下降,70%和50%负荷时分别下降了31.2%和17.0%;适当降低运行氧体积分数,NO_x质量浓度有一定的降低,同时煤粉燃尽情况基本不变.To solve the problem of high NOx emission commonly occurring at furnace outlet of large-scale coal-fired boilers during medium and low load operation, numerical studies were conducted on the flow, heat transfer, combustion and pollutant emission in a 1 000 MW ultra supercritical tower boiler, following which the problem was tackled by changing the damper openings of circumferential air and reducing the content of running oxygen. Results show that the simulation data agree well with actual measurements. During medium and low load operation, when the damper opening of circumferential air is reduced, the stoichiometric ratio is to be reduced in the initial period of combustion, while the NO, emission concentra- tion would be reduced accordingly by 31.2% and 17.0% respectively at 70% and 50% unit load. The NOx emission concentration can also be reduced by appropriately lowering the volumetric fraction of running ox- ygen, when the burnout rate of pulverized coal would basically keep constant.

关 键 词：塔式锅炉 NOX排放 周界风 运行氧体积分数 数值模拟 

分 类 号：TK227[动力工程及工程热物理—动力机械及工程]