CIESC Journal ›› 2016, Vol. 67 ›› Issue (12): 5237-5243.DOI: 10.11949/j.issn.0438-1157.20160733

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Characteristics of ash deposit and dew point corrosion in biofuel boiler

MA Haidong, WANG Yungang, ZHAO Qinxin, CHEN Heng, LIANG Zhiyuan, JIN Xin   

  1. Key Laboratory of Thermo-Fluid Science and Engineering(Ministry of Education), Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China
  • Received:2016-05-27 Revised:2016-09-23 Online:2016-12-05 Published:2016-12-05
  • Supported by:

    supported by the National Natural Science Foundation of China(51606144) and the Specialized Research Fund for the Doctoral Program of Higher Education(20130201110045).

生物质锅炉积灰特性与露点腐蚀

马海东, 王云刚, 赵钦新, 陈衡, 梁志远, 金鑫   

  1. 西安交通大学热流科学与工程教育部重点实验室, 陕西 西安 710049
  • 通讯作者: 王云刚。ygwang1986@mail.xjtu.edu.cn
  • 基金资助:

    国家自然科学基金项目(51606144);高等学校博士学科点专项科研基金项目(20130201110045)。

Abstract:

The coupling characteristics between ash deposit and dew point corrosion of deep-cooling flue gas on ND steel and 316 L stainless steel(control) was investigated in a 65 t·h-1 circulating fluidized bed biofuel boiler. The ash deposit and corrosion layer were studied by X-ray fluorescence spectroscopy(XRF), X-ray diffraction(XRD), scanning electron microscope(SEM) and energy dispersive spectrometer(EDS). Results indicated that the deposits on tube surface could be classified as layers of corrosion, coupling and ash deposit(NH4Cl、SiO2 and(NH4)2SO4). The coupling layer contained ash deposit and metal corrosion by-product, which was prone to spall off because of strong adhesion to the ash deposit layer. The corrosion layer, mainly composed of metal compounds of chlorides and oxides, reduced dramatically in thickness with the decrease of inlet water temperature. The degree of corrosion of ND steel increased sharply when wall temperature was below water dew point of flue gas. ND steel showed corrosion resistance inferior to 316 L stainless steel at experimental conditions.

Key words: corrosion, deposition, flue gas, biofuel

摘要:

以ND钢为研究对象,选取316 L不锈钢为对比材料,主要研究了65 t·h-1生物质循环流化床锅炉烟气深度冷却条件下的积灰与露点腐蚀耦合特性。对积灰和腐蚀层进行了XRF、XRD、SEM和EDS分析。实验结果表明:实验管件表面沉积物可分为腐蚀层、耦合层和灰沉积层(NH4Cl、SiO2和(NH42SO4)。耦合层包含了灰沉积物和金属腐蚀产物,且与灰沉积层黏结紧密易剥落;腐蚀层多为金属的氯化物和氧化物,其厚度随实验进口水温降低而降低,当管壁温低于烟气水露点时,ND钢被腐蚀的程度急剧加重。在实验条件下,ND钢的抗露点腐蚀能力弱于316L不锈钢。

关键词: 腐蚀, 沉积物, 烟道气, 生物燃料

CLC Number: