Research on Slagging and High Temperature Corrosion Prevention and Control of a 1 000 MW Ultra Supercritical Double Tangentially Fired Boiler

doi:10.12096/j.2096-4528.pgt.21125

Abstract

Abstract:

Aiming at the problems of slagging and high temperature corrosion of water wall in a 1 000 MW ultra-supercritical double tangential boiler, the mechanism of slagging and high temperature corrosion of boiler was analyzed by X-ray diffraction (XRD) and X-ray fluorescence (XRF).The results show that the presence of sodium and calcium in coal reduces the ash melting point of coal, causing boiler slagging. Sulfide-type high temperature corrosion is the main type of high temperature corrosion of the boiler. Through coal blending optimization and air distribution adjustment, the coal quality feeding into the furnace and the air distribution mode of the burner were optimized. The results show that selecting low-sulfur and low-slagging coal for blending can effectively alleviate the problem of slagging in the furnace. The increase of the total air volume of the boiler and the reasonable adjustment of the secondary air distribution of the burner can effectively reduce the concentration of the reducing atmosphere in the furnace, and alleviate the problem of high temperature corrosion in the furnace. The prediction results of boiler corrosion tendency by numerical simulation method show that the high-temperature corrosion should be further prevented in the hot corner area of the furnace by adding adherent wind or water wall spraying.

Key words: pulverized coal boiler, double tangential combustion, slagging, high temperature corrosion, reducing atmosphere

CLC Number:

TK 224

Shengli LIU, Haijun ZHANG, Jian CHENG, Yuxiu ZHONG, Jun XU, Long JIANG, Yi WANG, Sheng SU, Song HU, Jun XIANG. Research on Slagging and High Temperature Corrosion Prevention and Control of a 1 000 MW Ultra Supercritical Double Tangentially Fired Boiler[J]. Power Generation Technology, 2023, 44(2): 171-182.

Figures/Tables 18

References 25

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暴露面		基体结合面
元素组成	质量分数/%	元素组成	质量分数/%
Al	33.50	Al	4.83
Si	38.29	Si	3.74
S	12.03	S	22.57
Fe	12.65	Fe	68.21
Mn	0.25	Mn	0.43
Ti	1.32	Cu	0.08
K	1.96	Cr	0.14
Fe/S	1.05	Fe/S	3.02

暴露面		基体结合面
元素组成	质量分数/%	元素组成	质量分数/%
Al	33.50	Al	4.83
Si	38.29	Si	3.74
S	12.03	S	22.57
Fe	12.65	Fe	68.21
Mn	0.25	Mn	0.43
Ti	1.32	Cu	0.08
K	1.96	Cr	0.14
Fe/S	1.05	Fe/S	3.02

煤质特性		设计煤种	备选煤种编号
煤质特性		设计煤种	1	2	3	4	5	6	7	8	9	10
元素分析	w(C)/%	53.41	69.29	59.15	55.51	63.18	55.92	44.50	45.31	51.86	53.75	61.08
	w(H)/%	3.16	3.17	3.11	2.99	3.66	3.17	2.94	3.13	2.41	3.20	3.21
	w(N)/%	0.65	1.10	0.89	1.09	1.03	0.76	0.88	0.64	0.68	0.58	1.04
	w(S)/%	1.20	1.63	1.99	0.62	0.60	2.26	1.01	0.33	1.50	1.10	2.33
	w(O)/%	6.21	1.65	0.63	4.08	3.62	5.33	4.79	10.62	1.70	6.83	1.43
工业分析	M_ar/%	6.05	6.08	5.70	13.20	6.21	3.94	14.29	8.52	8.81	12.08	5.83
	A_ar/%	29.32	17.08	28.53	22.51	21.70	28.62	31.61	31.45	33.04	22.46	25.08
	V_ar/%	21.20	7.38	7.18	10.70	27.07	9.84	20.10	28.33	7.77	22.55	7.39
	F_Car/%	43.43	69.46	58.59	53.59	45.02	57.60	34.00	31.70	50.38	42.91	61.70
高位发热量/(MJ/kg)		20.78	26.98	22.32	21.97	23.61	16.27	17.60	16.66	18.96	20.70	24.11
低位发热量/(MJ/kg)		20.02	26.11	21.50	20.97	22.63	15.23	16.60	15.74	18.20	19.68	23.25

煤质特性		设计煤种	备选煤种编号
煤质特性		设计煤种	1	2	3	4	5	6	7	8	9	10
元素分析	w(C)/%	53.41	69.29	59.15	55.51	63.18	55.92	44.50	45.31	51.86	53.75	61.08
	w(H)/%	3.16	3.17	3.11	2.99	3.66	3.17	2.94	3.13	2.41	3.20	3.21
	w(N)/%	0.65	1.10	0.89	1.09	1.03	0.76	0.88	0.64	0.68	0.58	1.04
	w(S)/%	1.20	1.63	1.99	0.62	0.60	2.26	1.01	0.33	1.50	1.10	2.33
	w(O)/%	6.21	1.65	0.63	4.08	3.62	5.33	4.79	10.62	1.70	6.83	1.43
工业分析	M_ar/%	6.05	6.08	5.70	13.20	6.21	3.94	14.29	8.52	8.81	12.08	5.83
	A_ar/%	29.32	17.08	28.53	22.51	21.70	28.62	31.61	31.45	33.04	22.46	25.08
	V_ar/%	21.20	7.38	7.18	10.70	27.07	9.84	20.10	28.33	7.77	22.55	7.39
	F_Car/%	43.43	69.46	58.59	53.59	45.02	57.60	34.00	31.70	50.38	42.91	61.70
高位发热量/(MJ/kg)		20.78	26.98	22.32	21.97	23.61	16.27	17.60	16.66	18.96	20.70	24.11
低位发热量/(MJ/kg)		20.02	26.11	21.50	20.97	22.63	15.23	16.60	15.74	18.20	19.68	23.25

指标	结焦倾向
指标	轻微	中等	严重
酸碱比(B/A)	<0.206	0.206~0.400	>0.400
硅比(G)	>78.8	78.8~66.1	<66.1
硅铝比(X)	<1.87	1.87~2.65	>2.65
铁钙比(Y)	<0.3或>3.0	0.3~3.0	接近1.0
综合指数(R)	<1.5	1.5~2.5	>2.5