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浙江大学学报(工学版)
Journal of ZheJiang University (Engineering Science)  2020, Vol. 54 Issue (3): 623-630    DOI: 10.3785/j.issn.1008-973X.2020.03.024
Energy Engineering     
Effect of additives on flow characteristics and sodium capture efficiency of high alkali coal ash slag
Chen-ying ZHOU(),Hao ZHOU*(),Yu-jian XING,Jia-kai ZHANG,Ming-xi ZHOU
State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
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Abstract  

The flow characteristics of Zhundong coal ash slag with different mass percentages of SiO2, CaO, Fe2O3 and MgO in air atmosphere were investigated by using corundum slope in the horizontal tube furnace, in order to provide theoretical basis for the safe combustion of Zhundong high alkali coal in Slag-tap Boiler. The sodium content of coal ash slag was analyzed by XRF technology, and the sodium capture efficiency was used to characterize the sodium fixation effect of coal ash slag. Results show that SiO2 and Fe2O3 can promote the melting of Zhundong coal ash. When the mass fraction of SiO2 was 10%, the type of coal ash slag gradually changed from crystalline slag to vitreous slag, thus greatly improving the slag flow performance. Conversely, CaO and MgO can inhibit the melting of coal ash, resulting in degradation of flow properties. With the increase of SiO2 addition ratio, the sodium capture efficiency of slag increased gradually. When the addition ratio reached 10%, the sodium capture efficiency increased from 23% to 30%. On the contrary, the sodium capture efficiency decreased slowly with the increase of Fe2O3 addition ratio. Therefore, adding 10% SiO2 can effectively improve the fluidity of coal ash slag and the efficiency of sodium capture.

Key words： Zhundong high alkali coal      high temperature slag      additives      fluidity      sodium capture efficiency     
Received: 12 October 2018      Published: 05 March 2020
CLC:  TK 16  
Corresponding Authors: Hao ZHOU     E-mail: 18958088131@126.com;zhouhao@cmee.zju.edu.cn
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Chen-ying ZHOU
Hao ZHOU
Yu-jian XING
Jia-kai ZHANG
Ming-xi ZHOU
Cite this article:

Chen-ying ZHOU,Hao ZHOU,Yu-jian XING,Jia-kai ZHANG,Ming-xi ZHOU. Effect of additives on flow characteristics and sodium capture efficiency of high alkali coal ash slag. Journal of ZheJiang University (Engineering Science), 2020, 54(3): 623-630.

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http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2020.03.024     OR     http://www.zjujournals.com/eng/Y2020/V54/I3/623


添加剂对高碱煤灰渣流动特性及钠捕获效率的影响

为了给液态排渣锅炉安全燃烧准东高碱煤提供理论依据，在水平管式炉上利用刚玉斜坡对添加不同质量分数 SiO2、CaO、Fe2O3和MgO的准东煤灰渣在空气气氛下的流动性能进行研究. 利用XRF技术对煤灰渣的钠质量分数进行分析，并通过钠捕获效率来表征煤灰渣的固钠效果. 研究表明：SiO2和Fe2O3能够促进准东煤灰熔融.当SiO2的质量分数为10% 时，煤灰渣由结晶渣逐渐转变为玻璃体渣，流动性能大大提高；而CaO和MgO则会抑制煤灰熔融，导致流动性能降低. 随着SiO2添加比例的增加，灰渣对钠的捕获效率逐渐升高，当SiO2的质量分数达10%时，钠捕获效率由原先的23%上升至30%；而随着Fe2O3添加比例的增加，钠捕获效率缓慢降低. 因此，当SiO2的质量分数为10%时即可有效改善煤灰渣的流动性能，又能提高钠的捕获效率.


关键词： 准东高碱煤,  高温灰渣,  添加剂,  流动特性,  钠捕获效率 
类别 名称 测试数据
工业分析(%) Mad 15.6
Vd 32.79
Ad 12.3
FCd 54.91
元素分析(%) C 64.07
H 3.58
N 0.65
S 0.18
O 19.22
灰熔点(°C) DT 1 174
ST 1 258
HT 1 263
FT 1 267
Tab.1 Proximate analysis，ultimate analysis，and ash melting temperature of Zhundong coal
%
序号 名称 数据 序号 名称 数据
1 Na2O 7.60 7 Cl 10.72
2 MgO 2.90 8 K2O 0.33
3 Al2O3 14.50 9 CaO 27.46
4 SiO2 27.43 10 TiO2 0.87
5 P2O5 0.03 11 MnO 0.07
6 SO3 3.82 12 Fe2O3 4.26
Tab.2 Chemical composition of Zhundong coal ash
Fig.1 Sketch map of experimental device for fluidity of coal ash slag
Fig.2 Sketch map of slope for fluidity experimental of coal ash slag
Fig.3 Fluidity of Zhundong coal ash slag with different mass fraction of SiO2
Fig.4 Fluidity of Zhundong coal ash slag with different mass fraction of Fe2O3
Fig.5 Fluidity of Zhundong coal ash slag with different mass fraction of MgO
Fig.6 Fluidity of Zhundong coal ash slag with different mass fractions of CaO
°C
样品 θD θS θH θF
纯煤灰 1 174 1 258 1 263 1 267
w (SiO2)=5% 1 170 1 179 1 185 1 196
w (SiO2)=10% 1 165 1 176 1 180 1 182
w (SiO2)=20% 1 164 1 169 1 173 1 178
w (Fe2O3)=5% 1 167 1 193 1 205 1 222
w (Fe2O3)=10% 1 154 1 186 1 198 1 211
w (Fe2O3)=20% 1 146 1 170 1 175 1 178
Tab.3 Ash fusion test of Zhundong coal ash samples with different additives
Fig.7 Viscosity-temperature curve of pure Zhundong coal ash
Fig.8 Viscosity-temperature curve of coal ash with mass fraction of SiO2 of 10%
Fig.9 Viscosity-temperature curve of coal ash with mass fraction of Fe2O3 of 10%
Fig.10 Zhundong coal ash slag with different mass fractions of SiO2
Fig.11 Zhundong coal ash slag with different mass fractions of Fe2O3
%
灰渣成分 纯煤灰 w (SiO2) w (Fe2O3)
5% 10% 5% 10%
Na2O 1.88 2.20 2.27 1.68 1.59
MgO 2.64 2.49 2.34 2.39 2.30
Al2O3 18.06 16.75 15.19 16.77 16.09
SiO2 37.90 42.71 44.15 34.32 33.28
P2O5 0.04 0.03 0.04 0.04 0.04
SO3 0.63 0.78 0.76 0.41 0.31
Cl 0.65 1.02 1.09 0.43 0.30
K2O 0.05 0.07 0.08 0.04 0.03
CaO 24.72 24.08 22.70 22.89 22.69
TiO2 0.85 0.85 0.77 0.80 0.78
Fe2O3 11.07 8.72 8.29 17.13 21.74
Tab.4 XRF analysis of coal slag with different additives
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