前后对冲燃烧锅炉冷灰斗高温腐蚀原因识别及改进措施  

Identification and improvement measures of the high-temperature corrosion cause of the front and rear hedge combustion mode boiler cold ash bucket

作　　者：陈辉 张强 戴维葆 CHEN Hui;ZHANG Qiang;DAI Weibao(China Energy Science and Technology Research Institute,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,江苏南京210023

出　　处：《电力科技与环保》2023年第4期361-370,共10页Electric Power Technology and Environmental Protection

基　　金：国家能源投资集团有限责任公司科技项目(GJNY-19-139)。

摘　　要：某电厂600 MW超临界前后对冲燃烧方式锅炉后墙冷灰斗区域高温腐蚀严重。为了摸清高温腐蚀原因和减轻高温腐蚀,通过摸底诊断试验发现锅炉后墙冷灰斗区域壁面氛围参数中CO浓度分布在11.2×10^(4)~13.3×10^(4)μL/L,H_(2)S浓度分布在688~782μL/L,后墙底层B磨煤粉细度整体较前墙底层E磨偏小,并且E磨1#和3#粉管煤粉细度严重偏大,达38%,造成前后墙对冲火焰刚性不一致,B磨燃烧器火焰在对冲过程中容易被E磨燃烧器气流往下压制,火焰整体往下卷吸至冷灰斗区域,煤粉颗粒沉积在后墙冷灰斗区域,造成该区域还原性气氛偏高和高温腐蚀问题加剧。针对问题原因采用燃烧组织定向调整试验方法,调整E磨煤粉细度、一次风压和B磨煤粉细度有利于提高后墙火焰刚性,降低后墙冷灰斗壁面氛围参数。经过调整,后墙冷灰斗区域壁面氛围中CO浓度降低值范围为2.75×10^(4)~7.7×10^(4)μL/L,H_(2)S浓度降低值范围为120~355μL/L。优化调整无法根本上解决冷灰斗区域高温腐蚀,但对减轻高温腐蚀有积极的作用。优化调整结合贴壁风改造和防高温腐蚀喷涂改造是解决冷灰斗区域高温腐蚀问题的有效路径,为同类型机组运行和改造提供参考依据。The high-temperature corrosion in the rear cold ash bucket of 600MW supercritical front and rear hedge combustion mode boiler in a power plant is serious.In order to understand the causes of high-temperature corrosion and reduce high-temperature corrosion,through diagnostic test,it is found that the CO concentration in the atmosphere parameters in the rear wall bucket of the boiler is 11.2×10^(4)~13.3×10^(4)μL/L,and the H_(2)S concentration is 688~782μL/L,fineness of the B coal mill under the rear wall is smaller than the E coal mill under the front wall,and E coal mill 1#and 3#powder pipe coal fineness is seriously large,up to 38%,causing the front and rear wall hedge flame rigidity is inconsistent,the flame of the B coal mill burner is easily compressed by the air flow of the E coal mill burner during the hedging process,and the flame is rolled down to the cold ash bucket area.The pulverized coal particles are deposited in the cold ash bucket area of the rear wall,resulting in the high reducing atmosphere and the high-temperature corrosion problems in this area.According to the cause of the problem,the combustion tissue directional adjustment test method is adopted to adjust the fineness of E coal mill,primary wind pressure and B coal mill is conducive to improve the flame rigidity of the rear wall and reduce the atmosphere parameters of the rear wall cold ash bucket wall.After adjustment,the decrease of CO concentration in the wall atmosphere of the cold ash bucket area of the rear wall is from 2.75×10^(4)to 7.7×10^(4)μL/L,and the decrease of H_(2)S concentration is from 120 to 355μL/L.The optimization and adjustment cannot fundamentally solve the high-temperature corrosion in the cold ash bucket area,but it has a positive effect on reducing the high-temperature corrosion.Optimization and adjustment combined with wall wind transformation and anti-high temperature corrosion spraying transformation is an effective way to solve the problem of high-temperature corrosion in the cold ash bucket area,providin

关 键 词：超临界机组 前后对冲锅炉 冷灰斗 高温腐蚀 燃烧组织定向调整 

分 类 号：TK229[动力工程及工程热物理—动力机械及工程] TM621.2[电气工程—电力系统及自动化]