Prediction model of ash fusion temperature and viscosity in coal gasification
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摘要: 根据煤灰中硅铝含量及硅铝比对煤灰进行分类研究, 构建了灰熔融点和黏度与组分关系的优化模型, 并对宽组分范围的煤灰熔点、黏度关系进行探讨。获得了更加精确的灰熔点预测模型, 全液相温度模型预测误差为±40 ℃, 实验值和预测值的标准误差为25 ℃。采用修正的Urbain模型和Roscoe模型相结合, 模型预测值和实验值吻合较好, 低黏度下对数黏度的预测值和实验值误差为±0.1;高黏度下黏度的预测值和实验值误差为±0.2。结果表明, 基于煤灰组分分类的拟合结果优于涵盖宽组分的模型。Abstract: Based on classification of silica and alumina content and silica alumina ratio in coal ash, optimized prediction models of coal ash melting point and viscosity related to ash components were built. Their relationship in a wide range of ash components was also discussed. An ash fusion temperature prediction model based on liquidus temperature from FactSage Thermodynamic software demonstrates accuracy improvement with error of less than ±40 ℃ and deviation of 25 ℃. The combination of Urbain and Roscoe model results in viscosity prediction error between prediction and experiment results within ±0.1 for relative low viscosity and ±0.2 for relative high viscosity. The results show that components classification model obtains better results than wide-covered model. Thus a better understanding of ash fusion mechanism is provided and gives reasonable guidance for blending and additives added to coal.
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Key words:
- coal gasification /
- ash fusion temperature /
- viscosity /
- prediction model
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图 1 硅铝含量(SiO2+Al2O3) 与灰熔点关系
Figure 1 Relationship between FT (ash fusion temperature) and (SiO2+Al2O3) content
图 4 全液相温度和灰熔点线性拟合
Figure 4 Linear fit of FT and liquidus temperature
(a): high silica and alumina coal ash; (b): medium silica and alumina coal ash; (c): low silica and alumina coal ash; (d): high silica alumina ratio coal ash
图 7 熔渣黏度模型预测值和实验值对比
Figure 7 Comparison of slag viscosity between model results and experiment ones
表 1 煤灰样品中氧化物含量变化范围
Table 1 Content range of oxides in coal ash samples
Content w/% SiO2/Al2O3 SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O TiO2 Minimum 8.2 5.67 1.35 0.28 0.34 0.04 0.04 0.15 1.06 Maximum 66.7 37.57 41.88 46.88 13.06 3.9 4.73 3.09 6.94 
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表 2 煤灰分类依据
Table 2 Classification of coal ash
Classification Accordance of classification Sample numbers High silica and alumina coal ash SiO2+Al2O3 > 80% 30 Medium silica and alumina coal ash 60% < SiO2+Al2O3 < 80% 47 Low silica and alumina coal ash SiO2+Al2O3 < 60% 17 High silica alumina ratio coal ash SiO2/Al2O3 > 3 14
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表 3 熔点预测模型
Table 3 Ash fusion temperature prediction model
Ash classification Viscosity prediction equation Correlation coefficient High silica and alumina coal ash FT=0.962tliq-58.5 0.91 Medium silica and alumina coal ash FT=0.677tliq+298.5 0.93 Low silica and alumina coal ash FT=0.823tliq+111.4 0.90 High silica alumina ratio coal ash FT=0.925tliq+241 0.92
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表 4 灰熔点预测能力对比
Table 4 Prediction accuracy of ash fusion temperatures
Model Correlation coefficient Standard deviation t/℃ This research 0.91, 0.93, 0.90, 0.92 25 Jak 0.76 64 Chen wenmin - 47
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表 5 黏度模型灰成分
Table 5 Coal ash components in viscosity model
Coal ash Components content w/% SiO2/Al2O3 SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O TiO2 SiO2+Al2O3 Huangkuang 56.34 31.23 2.65 2.17 0.70 1.62 0.67 1.16 87.57 1.80 Bai 56.30 31.22 3.60 1.87 0.71 2.00 0.65 1.25 87.52 1.80 Yuwu 57.12 29.59 2.74 1.92 0.64 2.01 0.78 1.11 86.71 1.93 Wangzhuang 53.94 32.49 3.74 2.42 0.75 1.43 0.64 1.20 86.43 1.66 Anrui 45.18 36.11 8.52 1.32 0.66 1.30 0.32 1.21 81.29 1.25 Banjiao 66.24 14.79 4.09 7.14 1.30 1.49 0.82 0.88 81.03 4.48 Tongdaxinjing 42.70 35.03 6.52 5.48 2.16 0.94 0.22 1.39 77.73 1.22 4# 56.04 21.13 4.52 5.83 2.18 1.72 0.52 1.12 77.17 2.65 Cilinshan 45.34 30.87 7.48 7.40 0.46 0.46 0.04 0.97 76.21 1.47 Tianye1 52.09 20.15 7.58 7.78 2.70 2.18 0.76 0.98 72.24 2.59 Tianye 51.28 20.05 8.14 8.02 2.93 2.26 0.82 0.92 71.33 2.56 Yuncheng 45.22 7.89 28.4 5.12 3.18 0.94 0.78 0.46 53.11 5.73 6# 32.70 19.54 4.08 18.38 6.71 0.72 3.17 0.93 52.24 1.67 Tongliao 29.68 11.48 14.77 16.12 5.30 0.42 1.73 1.01 41.16 2.59
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表 6 修正的Urbain模型参数
Table 6 Modified Urbain model parameters
j i 0 1 2 3 bi0 0 12.45 35.21 -46.21 156.33 biC, j 1 -3.78 23.55 -49.09 33.90 2 4.02 -22.04 35.98 -17.89 biM, j1 1 -17.09 -22.34 37.65 -19.22 2 27.90 -122.88 179.01 -90.2 biK, j1 1 13.09 69.07 132.90 -65.90 2 -6.55 22.52 -1.87 -89.08 biN, j1 1 10.77 -31.39 -10.33 59.90 2 -11.21 -1.33 134.44 -190.22 biT, j1 1 23.33 -129.3 198.2 -104.43 2 -34.76 165.22 -276.9 155.5
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表 7 基于组分分类的黏度预测模型
Table 7 Viscosity prediction model based on composition classification
Object Model High silica alumina ratio coal ash;
high silica and alumina coal ash;See Table 6 high temperature melting zone of
medium silica and alumina coal ashSolid precipitation zone of medium
and low silica and alumina coal ashηe=η(1-1.211θ)-2.5
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