基于多参数深度优化降低锅炉省煤器出口CO和NOx浓度的试验研究  

The Experimental Study on Reducing the Outlet CO and NOx Concentration of Boiler Economizer Based on Multi-parameter Depth Optimization

作　　者：王圣 陈辉 张天翼 胡耘 WANG Sheng;CHEN Hui;ZHANG Tian-yi;HU Yun(State Key Laboratory of Clean and Efficient Coal-fired Power Generation and Pollution Control,China Energy Science and Technology Research Institute Co.,Ltd.,Nanjing 210023,China)

机构地区：[1]国家能源集团科学技术研究院有限公司清洁高效燃煤发电与污染控制国家重点实验室,南京210023

出　　处：《电力学报》2022年第6期507-514,共8页Journal of Electric Power

基　　金：国家能源集团2022年科技专项(GJNY-22-89);国家重点研发专项(2022YFC3701504)。

摘　　要：某电厂2#600 MW超临界机组锅炉在高负荷运行时,存在省煤器出口CO和NO_(x)浓度偏高的问题,严重影响锅炉运行的经济性、安全性和环保性。开展摸底诊断试验分析CO和NO_(x)浓度偏高的原因,分析得知,省煤器出口氧量分布不均匀和煤粉细度不合适是造成CO浓度偏高的主要原因,同时煤粉细度的不合适还会造成省煤器出口NO_(x)浓度、过热减温水量和飞灰含碳量的增加。在锅炉深度低氮燃烧状态下,通过深度优化煤粉细度数值,省煤器出口NO_(x)质量浓度由调整前的308 mg/Nm^(3)下降至251 mg/Nm^(3),降幅约18.51%,省煤器出口的CO体积浓度由1298μL/L降低至830μL/L。过热减温水量降低7 t/h,飞灰含碳量(质量分数)由2.10%降低至0.84%,降低1.26百分点。通过调整燃烧器外二次风门开度、SOFA风外二次风门开度改善省煤器出口氧量分布,氧量(体积分数)偏差最大值由调整前的4.7百分点下降至1.5百分点,省煤器出口CO体积浓度由830μL/L下降至340μL/L。经过优化调整,锅炉效率提高约0.68百分点,影响煤耗降低约2.04 g/(kW·h)。锅炉运行经济性、安全性和环保性得到较大提高,为同类型机组运行提供参考依据。During high load operation of 2#600 MW supercritical unit boiler in a power plant,there is a problem of high CO and NO_(x)concentration of economizer outlet.It seriously affects the economy,safety and environmental protection of boiler operation.To conduct diagnostic mapping tests to analyze the causes of high CO and NO_(x)concentrations,due to the uneven distribution of oxygen at the outlet of economizer and the improper fineness of pulverized coal,the CO concentration is high,at the same time,the improper fineness of pulverized coal will also lead to the increase of NO_(x)concentration,overheating and temperature reduction,and carbon content of fly ash.Under the condition of low nitrogen combustion,optimization of pulverized coal fineness by depth,NO_(x)concentration at economizer outlet decreases to 251 mg/Nm^(3)from 308 mg/Nm^(3)before adjustment,with a decrease of about 18.51%,CO concentration at economizer outlet decreases from 1298μL/L to 830μL/L,overheating desuperheating water decreases 7 t/h,and the carbon content of fly ash decreases from 2.10%to 0.84%,with a decrease of 1.26 percentage points.By adjusting the opening of the secondary air valve outside the burner and SOFA the opening of the secondary air valve outside the burner,the oxygen distribution at the outlet of the economizer is improved,the maximum deviation of oxygen content decreased from 4.7 percentage points before adjustment to 1.5 percentage points,and CO concentration at economizer outlet decreases from 830μL/L to 340μL/L.After optimization,Boiler efficiency increases by about 0.68 percentage points,about 2.04 g/(kW·h)less coal.The economy,safety and environmental protection of the boiler are improved,to provide reference for the operation of the same type of unit.

关 键 词：超临界机组 锅炉 CO浓度 NOx浓度 煤粉细度 优化运行 

分 类 号：TM621[电气工程—电力系统及自动化]