Analysis on Corrosion Causes of Induced Draft Fan Blade in Circulating Fluidized Bed Boiler With Mixed Burning Solid Waste Fuel

doi:10.12096/j.2096-4528.pgt.20055

Abstract

Abstract:

In order to study the reasons for serious corrosion problem of induced draft fan blades of a 2×300 MW circulating fluidized bed unit which were blended burning solid waste fuel, the samples of the corroded blade and ash from different positions were taken. The analysis results of X-Ray diffractomer (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) show that Cl element is found in the rust samples and on the surface of the blades, and no trace of S element is found. Therefore, it is determined that the cause of the corrosion of the blades is Cl corrosion. Through the test of ash samples at different positions of the boiler, it is found that the ash hardened on the air preheater and the ash collected by bag filter behind the semi-dry flue gas desulfurization are enriched in Cl, which is the key to cause the Cl corrosion of the equipment. The blended burning solid waste fuel and sludge are the main sources of Cl. The enrichment of Cl in the ash hardened on the air preheater is found related to NH₃ escaped from selective non-catalytic reduction, the reason of Cl enrichment in desulfurized ash needs further study.

Key words: circulating fluidized bed, boiler, solid waste fuel, blade corrosion, Cl corrosion

CLC Number:

TK16

Guohua QIU, Pengzhi XU. Analysis on Corrosion Causes of Induced Draft Fan Blade in Circulating Fluidized Bed Boiler With Mixed Burning Solid Waste Fuel[J]. Power Generation Technology, 2020, 41(6): 681-688.

Figures/Tables 15

References 20

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参数	设计煤种	校核煤种
收到基碳C_ar/%	57.28	52.30
收到基氢H_ar/%	1.16	1.04
收到基氧O_ar/%	1.02	0.83
收到基氮N_ar/%	0.56	0.71
收到基硫S_t.ar/%	0.98	1.12
全水分M_t/%	9	12
收到基灰分A_ar/%	30	32
空干基水分M_ad/%	1.56	1.61
干燥无灰基挥发分V_daf/%	3.8	3.2
收到基低位发热量Q_net.ar/(MJ/kg)	20.68	19.07

参数	设计煤种	校核煤种
收到基碳C_ar/%	57.28	52.30
收到基氢H_ar/%	1.16	1.04
收到基氧O_ar/%	1.02	0.83
收到基氮N_ar/%	0.56	0.71
收到基硫S_t.ar/%	0.98	1.12
全水分M_t/%	9	12
收到基灰分A_ar/%	30	32
空干基水分M_ad/%	1.56	1.61
干燥无灰基挥发分V_daf/%	3.8	3.2
收到基低位发热量Q_net.ar/(MJ/kg)	20.68	19.07

参数	褐煤	烟煤	无烟煤
质量分数/%	58	35	7
全水分M_t/%	32.7	17.4	19.1
空干基灰分A_ad/%	6.0	17.0	35.6
空干基水分M_ad/%	20.6	7.4	4.1
空干基挥发分V_ad/%	36.9	28.8	7.2
空干基全硫S_t.ad/%	0.6	0.7	1.0
收到基低位热值Q_net.ar/(MJ/kg)	16.6	20.7	16.0

参数	褐煤	烟煤	无烟煤
质量分数/%	58	35	7
全水分M_t/%	32.7	17.4	19.1
空干基灰分A_ad/%	6.0	17.0	35.6
空干基水分M_ad/%	20.6	7.4	4.1
空干基挥发分V_ad/%	36.9	28.8	7.2
空干基全硫S_t.ad/%	0.6	0.7	1.0
收到基低位热值Q_net.ar/(MJ/kg)	16.6	20.7	16.0

序号	成分名称	质量分数/%
1	布料	68~70
2	毡类	17~19
3	塑料	5~8
4	橡胶	6~9
5	无机物	2.0~2.5
6	小分子有机物	1~2