Analysis and countermeasure of high temperature corrosion on water wall of coal-fired power plant boiler

doi:10.16085/j.issn.1000-6613.2020-0302

Abstract

Abstract:

The object of research is the high-temperature corrosion of the water-cooled wall of the utility boiler in the form of hedge combustion. The corrosion characteristics of the water-cooled wall combustion area are modeled and analyzed from the perspective of corrosion mechanism and combustion characteristics. The distribution of sulfide-type molten salt corrosion parts is distributed. The areas where severe corrosion occurs will be concentrated in the area around the burners on both sides of the wall, the area of the lower cold ash hopper, and the middle of the sides of the wall between the upper burner and the top burnout vent region.The verification of field measured data shows that when the oxygen concentration in the near wall of the water-cooled wall of a coal-fired power plant boiler is extremely low, the concentration of H₂S, CO and other substances exceeds the requirements of the corrosion judgment index.Combined with engineering experience, specific measures for high temperature corrosion prevention of water-cooled walls are given.

Key words: coal-fired power plant boiler, water wall, high temperature corrosion, analysis, countermeasures

摘要：

以对冲燃烧方式的电站锅炉水冷壁壁面高温腐蚀问题为研究对象，从腐蚀机理与燃烧特性角度对水冷壁燃烧区域进行腐蚀特性建模分析，研究水冷壁近壁区域还原性和腐蚀性气氛作用下的硫化物型熔盐腐蚀部位分布规律，腐蚀发生严重的区域将集中在两侧墙的燃烧器周围区域、下层冷灰斗区域、上层燃烧器与顶层燃尽风喷口之间的两侧墙中间区域。现场实测数据验证可知，燃煤电站锅炉水冷壁近壁区域在氧浓度极低情况下，H₂S、CO等物质浓度严重超出腐蚀判定指标要求，水冷壁壁面腐蚀严重，腐蚀发生部位与数值模型结果吻合。结合工程经验，给出了水冷壁壁面高温腐蚀防治的具体措施。

关键词: 燃煤电站锅炉, 水冷壁, 高温腐蚀, 分析, 对策

CLC Number:

TK224.9

Yingli YU, Xuchen FU, Yingying DAI, Jun RONG, Zhengping GAO, Bin CAI, Junhu HU. Analysis and countermeasure of high temperature corrosion on water wall of coal-fired power plant boiler[J]. Chemical Industry and Engineering Progress, 2020, 39(S1): 90-96.

于英利, 付旭晨, 戴莹莹, 荣俊, 高正平, 蔡斌, 胡俊虎. 燃煤电站锅炉水冷壁壁面高温腐蚀问题分析与对策[J]. 化工进展, 2020, 39(S1): 90-96.

Figures/Tables 10

References 10

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项目名称	数值
一次风温/℃	70
二次风温/℃	354
磨煤机入口风温/℃	234
一次风速/m·s^-1	17.3
二次风速（内环）/m·s^-1	20.4
二次风速（外环）/m·s^-1	40.7
一次风比/%	24.6
煤粉细度R₉₀/%	20

项目名称	数值
一次风温/℃	70
二次风温/℃	354
磨煤机入口风温/℃	234
一次风速/m·s^-1	17.3
二次风速（内环）/m·s^-1	20.4
二次风速（外环）/m·s^-1	40.7
一次风比/%	24.6
煤粉细度R₉₀/%	20

位置	各成分浓度
位置	O₂体积分数/%	CO /μL·L^-1	H₂S /μL·L^-1	NO /μL·L^-1	SO₂ /μL·L^-1	CO₂体积分数/%
上层测孔
甲侧墙前孔	0.5	1570	978	79	88	18.6
甲侧墙中孔	0.2	18753	1486	37	659	18.3
甲侧墙后孔	0.7	1422	71	211	69	18.6
乙侧墙前孔	0.2	23125	738	44	295	17.9
乙侧墙中孔	0.2	19895	1633	59	732	18.2
乙侧墙后孔	0.9	7783	164	260	233	17.6
中层测孔
甲侧墙前孔	0.3	2384	760	45	117	18.3
甲侧墙中孔	0.6	8590	1396	25	176	18.2
甲侧墙后孔	0.4	6211	1288	137	103	18.8
乙侧墙前孔	0.3	9782	1162	32	279	18.1
乙侧墙中孔	0.4	13793	1346	31	292	18.0
乙侧墙后孔	0.6	9159	894	380	244	17.9
下层测孔
甲侧墙前孔	0.4	646	891	24	476	18.9
甲侧墙中孔	0.5	10962	745	19	134	18.6
甲侧墙后孔	0.3	679	697	332	645	18.8
乙侧墙前孔	0.4	4880	943	17	460	18.6
乙侧墙中孔	0.5	14658	492	63	1398	17.8
乙侧墙后孔	0.2	13722	327	261	348	17.8

位置	各成分浓度
位置	O₂体积分数/%	CO /μL·L^-1	H₂S /μL·L^-1	NO /μL·L^-1	SO₂ /μL·L^-1	CO₂体积分数/%
上层测孔
甲侧墙前孔	0.5	1570	978	79	88	18.6
甲侧墙中孔	0.2	18753	1486	37	659	18.3
甲侧墙后孔	0.7	1422	71	211	69	18.6
乙侧墙前孔	0.2	23125	738	44	295	17.9
乙侧墙中孔	0.2	19895	1633	59	732	18.2
乙侧墙后孔	0.9	7783	164	260	233	17.6
中层测孔
甲侧墙前孔	0.3	2384	760	45	117	18.3
甲侧墙中孔	0.6	8590	1396	25	176	18.2
甲侧墙后孔	0.4	6211	1288	137	103	18.8
乙侧墙前孔	0.3	9782	1162	32	279	18.1
乙侧墙中孔	0.4	13793	1346	31	292	18.0
乙侧墙后孔	0.6	9159	894	380	244	17.9
下层测孔
甲侧墙前孔	0.4	646	891	24	476	18.9
甲侧墙中孔	0.5	10962	745	19	134	18.6
甲侧墙后孔	0.3	679	697	332	645	18.8
乙侧墙前孔	0.4	4880	943	17	460	18.6
乙侧墙中孔	0.5	14658	492	63	1398	17.8
乙侧墙后孔	0.2	13722	327	261	348	17.8

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