贫煤锅炉全烧烟煤燃烧器改造技术研究  

Study on the Transformation Technology of Bituminous Coal Burner in Lean Coal Boiler

作　　者：陈辉 赖金平 戴维葆 方亚雄 王睿 CHEN Hui;LAI Jinping;DAI Weibao;FANG Yaxiong;WANG Rui(National Energy Group Science and Technology Research Institute Co.,Ltd.,Nanjing 210031,China)

机构地区：[1]国家能源集团科学技术研究院有限公司,南京210031

出　　处：《电力学报》2024年第2期101-110,共10页Journal of Electric Power

基　　金：国家能源集团2022年科研专项(DY2022Y05)。

摘　　要：以某600 MW超临界前后对冲燃烧方式锅炉为研究对象,该锅炉煤种由贫煤更换为低灰熔点烟煤后存在炉膛结渣严重问题,分析发现燃烧系统改造时需考虑降低燃烧器区域热负荷,防止燃烧器区域温度过高引起炉膛发生严重结渣;为防止炉膛火焰中心上移,不能过多降低燃烧器区域热负荷,否则可能引起屏式过热器结渣、再热器超温、减温水量大、稳燃能力不足等问题。在改造方案中,将其上层燃烧器整体抬高2 500 mm,中层燃烧器整体抬高500 mm;改造后,中上层燃烧器的层间距为6 742 mm,中层与下层燃烧器层间距为5 242 mm。通过燃烧器不等间距布置,在THA工况下,可大幅降低燃烧器区域壁面热负荷至1.39 MW/m^(2);机组50%负荷及以上时,主汽温度达到571℃,再热汽温达到569℃,锅炉效率大于94%,炉膛出口烟气温度为1 000℃,高温再热器进口烟气温度为984℃,均低于燃用煤种灰熔点,可以较好地预防受热面结渣和燃烧器附近结渣。省煤器出口CO体积浓度最大为180μL/L,NOx质量浓度最大为235 mg/m^(3)(N),各项参数均满足改造目标要求。A 600 MW supercritical before and after hedge combustion boiler is taken as the research object.The boiler coal is replaced from lean coal to low ash melting point bituminous coal.The study found that the combus-tion system transformation should reduce the heat load of the burner area,so as to prevent the high temperature of the burner area from leading to serious coking of the furnace.At the same time,the heat load of the burner ar-ea should not be reduced too much to prevent the flame center of the furnace from moving up,resulting in the screen superheater dreling,reheater overtemperature,large temperature water reduction,insufficient stable combustion capacity and other problems.The upper burner is raised 2500 mm,and the middle burner is raised 500 mm.After the transformation,the spacing between the upper burner layer is 6742 mm,and the spacing be-tween the middle and lower burner layer is 5242 mm.Through the burner unequal spacing arrangement,the wall heat load of the burner under THA conditions can be greatly reduced to 1.39 MW/m^(2);50%load and above,the main steam temperature reaches 571℃,the reheat steam temperature reaches 569℃,the boiler effi-ciency is greater than 94%,the furnace outlet flue gas temperature is 1000℃,and the high inlet flue gas tem-perature is 984℃,which is lower than the melting point of coal ash,which can prevent the heating surface cok-ing and coking near the burner.The maximum CO concentration at the outlet of the economizer is 180μL/L,the maximum NO_(x) concentration is 235 mg/m^(3)(N),and all the parameters meet the requirements of the trans-formation target.

关 键 词：超临界 贫煤锅炉 烟煤 燃烧器改造 结渣 

分 类 号：TM621.2[电气工程—电力系统及自动化]