Study on the operation optimization of 350 MW supercritical pulverized coal-fired boiler firing 100％ Zhundong coal

doi:10.3969/j.issn.1674-1951.2021.12.012

Abstract

Abstract:

In order to alleviate the slagging and fouling on the heating surface of Zhundong coal in its pure combustion,the co-combustion of Zhundong coal and kaolin was tested in a 350 MW supercritical pulverized coal boiler for 397 days.All parameters of this test have met the requirements of stable operation of the boiler.A 120 h hot-state debugging can improve the operation state of the boiler taking co-combustion.The optimal oxygen content of the boiler under 310 MW working condition should be maintained between 2.8%~3.2%.The study points out that the five mills should be put into operation first during boiler high-load operation,and the distribution of the coal feed rates should be in pyramid shape,namely the coal feed rate of the upper-layer mill should be smaller and that of the lower-layer mill should be higher.Furthermore,comprehensively considering the NOx emission concentration,the opening of OFA throttles should be kept as small as possible and the distribution of the secondary air should be in pyramid shape as well.The co-combustion test and hot-state debugging make the Zhundong coal pure combustion feasible on the 350 MW supercritical boiler.

Key words: Zhundong coal, kaolin, co-combustion, hot-state debugging, supercritical boiler

CLC Number:

TK16

LIU Yibin, LIU Xuankun, SONG Gang, YANG Xinhua, ZHANG Man, YANG Hairui. Study on the operation optimization of 350 MW supercritical pulverized coal-fired boiler firing 100％ Zhundong coal[J]. Huadian Technology, 2021, 43(12): 79-84.

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项目	BMCR	额定出力
过热蒸汽流量/(t·h^-1)	1 190	1 131
过热器出口蒸汽压力/MPa	25.4	25.3
过热器出口蒸汽温度/℃	571	571
再热蒸汽流量/(t·h^-1)	944.4	895.0
再热器进口蒸汽压力/MPa	4.5	4.2
再热器出口蒸汽压力/MPa	4.29	4.10
再热器进口蒸汽温度/℃	322	315
再热器出口蒸汽温度/℃	569	569
省煤器进口给水温度/℃	289	285
计算热效率/%	93.9	93.9

项目	设计煤种	校核煤种
ω（C）/%	56.11	61.20
ω（H)/%	2.58	3.43
ω（O)/%	9.77	10.33
ω（N)/%	0.47	0.60
ω（S)/%	0.48	0.60
ω（C_ar）/%	27.20	14.80
灰分/%	3.39	9.04
水分/%	11.41	7.24
挥发分/%	30.41	35.32
低位发热量/(MJ·kg^-1)	19.48	22.44
哈氏可磨系数	120	76

项目	数据	项目	数据
ω（SiO₂）/%	56.80	ω（SO₃）/%	0.13
ω（Al₂O₃）/%	28.42	ω（MnO₂）/%	0.17
ω（Fe₂O₃）/%	3.74	变形温度/℃	1 380
ω（CaO）/%	3.41	软化温度/℃	1 390
ω（MgO）/%	0.44	半球温度/℃	1 410
ω（Na₂O）/%	1.74	流动温度/℃	1 440
ω（K₂O）/%	2.39	哈氏可磨系数	121
ω（TiO₂）/%	1.97

高岭土掺配比例/%	变形温度/℃	软化温度/℃	半球温度/℃	流动温度/℃
5.0	1 086	1 087	1 125	1 132
5.5	1 120	1 143	1 164	1 178
6.0	1 160	1 183	1 192	1 206
6.5	1 216	1 217	1 218	1 218
7.0	1 146	1 161	1 176	1 206

项目		数据
燃尽风/（万m³⋅h^-1）	直流	40	40	40	40
燃尽风/（万m³⋅h^-1）	旋流	25	15	15	25
D层开度/（°）	内二次风	63	60	58	60
D层开度/（°）	外二次风	60	45	45	53
C层开度/（°）	内二次风	60	60	55	58
C层开度/（°）	外二次风	65	53	48	65
A层开度/（°）	内二次风	90	90	90	90
A层开度/（°）	外二次风	45	50	50	30
F层开度/（°）	内二次风	63	60	65	60
F层开度/（°）	外二次风	53	50	50	60
E层开度/（°）	内二次风	65	60	55	70
E层开度/（°）	外二次风	65	50	50	65
B层开度/（°）	内二次风	60	55	60	60
B层开度/（°）	外二次风	63	50	55	60