scholarly journals High temperature corrosion of water wall tube in coalfired combustion gases

1993 ◽  
Vol 03 (C9) ◽  
pp. C9-787-C9-796 ◽  
Author(s):  
K. Nakagawa ◽  
M. Kitagawa ◽  
Y. Tumita ◽  
S. Ooki
Keyword(s):  
High Temperature ◽  
High Temperature Corrosion ◽  
Combustion Gases ◽  
Water Wall ◽  
Water Wall Tube

Failure Analysis of the Corroded Water Wall Tube in a 50MW Thermal Power Plant

2018 ◽  
Vol 37 (9-10) ◽  
pp. 995-999 ◽  
Author(s):  
Guohua Yang ◽  
Yuanbo Gou ◽  
Xinshi Liu ◽  
Xiaoming Zhang ◽  
Tuo Zhang
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Thermal Power Plant ◽  
Energy Dispersive Spectrometer ◽  
Thermal Power ◽  
Effective Means ◽  
High Temperature Corrosion ◽  
Boiler Water ◽  
Water Wall ◽  
Water Wall Tube

AbstractHigh temperature corrosion of the water wall tube in a 50 MW thermal power plant was investigated which caused several boiler accidents. X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) were used to observe the cross-sectional morphology of the tube and analyze the oxide scales. Results show that the boiler water and the coal quality did not meet the requirements. High temperature corrosion of water wall tubes was attributed to the using of coal which had a higher ash content and lower received lower heating value. Higher dissolved oxygen and incrustation in the boiler water caused serious corrosion at the inner surface of water wall tube, which led to the possibility of decarburization and degradation of the steel. Suitable coal blending and stability of the thermal load were the effective means to prevent the high temperature corrosion of the tube.

Review on Reaction Mechanisms of Sulfur Species During Coal Combustion

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Honghe Ma ◽  
Lu Zhou ◽  
Sichen Lv ◽  
Jia Wei Chew ◽  
Zhijian Wang
Keyword(s):  
High Temperature ◽  
Reaction Mechanisms ◽  
Coal Combustion ◽  
High Temperature Corrosion ◽  
Sulfur Species ◽  
Water Wall ◽  
Adequate Knowledge ◽  
Hole Wall ◽  
High Concentrations ◽  
New Research

Various low-NOx combustion technologies have been widely applied as primary measures to limit NOx emission in coal-fired boilers. However, this leads to the formation of high concentrations of H2S in the fuel-rich zone and thus causes high-temperature corrosion of the water-wall. In order to suppress the formation of H2S near the water-wall, it is necessary to have adequate knowledge of the reaction mechanisms of sulfur species during coal combustion. Therefore, this work systematically reviews the current state-of-the-art concerning reaction mechanisms for sulfur species, including global mechanisms, detailed mechanisms, and reduced mechanisms. Additionally, two operation techniques, namely, near-wall air and multi-hole-wall air, are introduced to avoid high-temperature corrosion caused by H2S. Finally, some new research directions are recommended to further reveal the reaction mechanisms of sulfur species and to test the feasibility of multi-hole-wall air on preventing high-temperature corrosion.

Failure Analysis of Spiral Water Wall Tube Cracking in Ultra-Supercritical Power Plant Boiler

2016 ◽  
Author(s):  
Jun Si ◽  
Zhenrong Yan ◽  
Jianjun Chen
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Power Plant ◽  
Failure Analysis ◽  
Power Plants ◽  
Composition Analysis ◽  
Element Analysis ◽  
Water Wall ◽  
Water Wall Tube ◽  
Weld Heat

The efficiency of conventional boiler/steam turbine fossil power plants has strong relationship to the steam temperature and pressure. At present, steam temperatures of the most efficient fossil power plants are now in the 600°C range. Higher-strength materials are needed for upper water wall tube of boilers with steam pressure above 24 MPa. A high-strength 2.5%Cr steel recently approved by ASME code as T23 is the preferred candidate material for this application. Due to its superior properties, T23 steel is typically not post-weld heat treated. However, after several years running there are a lot of incident reports for T23 tubes especially the breakage of weldment in the ultra-supercritical power plant. This is cause for concern for T23 tubes weldment used under high temperature environments. Previous studies showed that the residual stress may play an important role to the performance of spiral water wall tube. In this paper, the distribution of residual stress in T23 tube weldment has been investigated in detail. Inner wall cracks were found at the butt-jointed seam region of spiral water wall tubes by radiographic testing after one year’s operation. Failure analysis of the spiral water wall tube cracking was conducted by chemical composition analysis, mechanical testing and finite element analysis in this paper. It was found that localized residual stress after the weld process caused concentrated stress, which is the primary reason for failure. Our studies illustrate the necessity of post weld heat treatment for the T23 tubes used under high temperature.

Study on high temperature corrosion mechanism of water wall tubes of 350 MW supercritical unit

2021 ◽  
Vol 121 ◽  
pp. 105131
Author(s):  
Xu Sun ◽  
Yuheng Ning ◽  
Jian Yang ◽  
Yong Zhao ◽  
Zhanjun Yang ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Corrosion ◽  
Corrosion Mechanism ◽  
Water Wall

Failure Analysis and Welding Repair for Water Wall Tube Burst of 600MW Station Boiler

2013 ◽  
Vol 706-708 ◽  
pp. 1339-1343
Author(s):  
Xiang Feng Zheng ◽  
Er Song Chen ◽  
Qing Wang ◽  
Ji Feng Zhao ◽  
Guo Zhen Dong ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
High Temperature ◽  
Operating Temperature ◽  
Mechanical Analysis ◽  
Strength Degradation ◽  
High Temperature Strength ◽  
High Temperature Creep ◽  
Water Wall ◽  
Water Wall Tube

Through methods, such as microscope analysis, mechanical analysis, chemical analysis, metallography examination etc, the causes resulting in water wall tube bursting of 600MW station boiler have been analyzed. The result indicates this water wall tube burst is the high temperature creep fracture. The higher operating temperature, microstructure aging and high temperature strength degradation are the primarily inducement of bursting failure. In welding tube, the measures of reducing residual stress, such as lower welding heat input, reducing thickness of welding layer, assigning reasonably heat treatment power, lengthening holding time and so on, were taken. The welding repair succeeded greatly.

High Temperature Corrosion of Water Wall Materials T23 and T24 in Simulated Furnace Atmospheres

2012 ◽  
Vol 20 (4) ◽  
pp. 814-822 ◽  
Author(s):  
Qinxin ZHAO ◽  
Zhixiang ZHANG ◽  
Dingnan CHENG ◽  
Yungang WANG ◽  
Xiang DENG
Keyword(s):  
High Temperature ◽  
High Temperature Corrosion ◽  
Water Wall ◽  
Wall Materials

Experimental Research on High Temperature Corrosion Prevention Technology for Water Wall of Opposed Wall Fired Ultra Supercritical Boiler

2014 ◽  
Vol 654 ◽  
pp. 69-73 ◽  
Author(s):  
Bo Jiang ◽  
Fu Guo Liu ◽  
Ke Liu ◽  
Hao Jie Liu
Keyword(s):  
High Temperature ◽  
Experimental Research ◽  
Flue Gas ◽  
Volume Fraction ◽  
High Temperature Corrosion ◽  
Wall Region ◽  
Water Wall ◽  
Swirl Intensity ◽  
Secondary Air ◽  
Near Wall

In order to solve the problem of high temperature corrosion to water wall of opposed wall fired ultra supercritical boiler, comprehensive study is carried out by combining theoretical analysis and experimental research, obtaining the variation of flue gas composition before and after introduction of near wall wind and effect of primary air velocity, central air opening, swirl intensity of outer secondary air and inner secondary air opening on composition of flue gas in near wall region. The results show that 1) the introduction of near wall wind significantly improves reducing atmosphere in near wall region; 2) among the four parameters listed above, swirl intensity of outer secondary air and inner secondary air opening have greater influence on composition of near wall flue gas; 3) under the comprehensive effect of swirl intensity of outer secondary air and inner secondary air opening, the volume fraction of CO in near wall flue gas can be controlled below 1500ppm, which effectively disturbs the condition for high temperature corrosion.

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