Two-dimensional Prediction for Silicon Content of Hot Metal of Blast Furnace Based on Bootstrap
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摘要: 高炉铁水硅含量的实时准确预报对调控高炉炉温和稳定炉况具有重要作用, 但其预报结果一直存在准确度不高和缺乏可信度表征等问题, 特别是在炉况不稳、运行数据波动较大时, 预报结果的准确度和可信度急速下降, 不利于现场操作人员根据预报结果进行生产操作. 为此本文融合神经网络和Bootstrap预报区间方法, 构建高炉铁水硅含量的二维预报模型, 实现在预报硅含量值的同时给出了该预测值的可信度.应用实例表明, 本文提出的方法提高了硅含量点预测结果的准确度, 且预测区间宽度能正确地表征点预测结果的可信度, 对实际生产操作具有较好的指导意义.Abstract: Accurate real-time forecasting of silicon content in hot metal of blast furnace plays a significant role in furnace temperature regulation, but the prediction results have a low hit rate and lack any indication of accuracy. Especially when furnace conditions are unstable and the data fluctuate frequently, the hit rate and the reliability decrease so sharply that workers cannot use the prediction results for manufacturing operation. Therefore, a two-dimensional prediction model of silicon content in hot metal based on the integration of Bootstrap method and neural network is constructed to predict the silicon content. Meanwhile, the reliability of point prediction is also provided. Application results show that not only does the model improve the prediction accuracy of silicon content in point shooting, but also the prediction interval width correctly characterizes the reliability of point prediction. The proposed method will be beneficial to the practical production process.
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Key words:
- Blast furnace /
- Bootstrap /
- two-dimensional prediction /
- prediction interval /
- reliability
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表 1 模型的候选输入变量
Table 1 List of candidate input variables of the model
变量名 单位 变量名 单位 Si(n-1) wt % 理论燃烧温度 ℃ Si(n - 2) wt % 矿焦比 kg/t 料速 t/h 标准风速 m/s 顶压 kpa 热风温度 oC 全压差 kpa 鼓风动能 kg . m/s 富氧率 wt % 冷风流量 m3/ min 热风压力 kpa 冷风压力 kpa 实际风速 m/s 富氧压力 kpa 喷煤量 t 透气性指数 m3/ min .kpa 表 2 模型的输入变量
Table 2 List of the input variables of the model
变量名 相关性 变量名 相关性 Si(n - 1) 0.731 富氧率 0.251 Si(n - 2) 0.618 热风温度 -0.214 冷风流量 0.378 料速 -0.207 实际风速 -0.342 透气性指数 -0.113 鼓风动能 -0.304 表 3 四种预测模型的硅含量值的预测结果对比
Table 3 Comparison of prediction results of the four models
方法 命中率(%) 均方根误差 单一神经网络 75 0.1251 偏最小二乘模型 70 0.1384 ARIMA模型 73 0.1297 二维预报模型 84 0.0735 表 4 二维预报模型的预测结果统计
Table 4 Statistics of prediction results of the two-dimensional
绝对误差 预测点个数 预测区间平均宽度 <0.05 101 0.3118 (0.05, 0.1) 67 0.3207 < 0.1 32 0.4744 表 5 硅含量预测区间宽度和点预测结果的可信度关系
Table 5 The relationship between width of prediction interval and reliability of point predictions
预测点个数 预测区间 预测区间宽度范围 < 0.1 < 0.1 共 可信度(%) Ri < 0.3 76 4 80 95% R2 (0.3, 0.45) 77 3 80 96.25% Rs < 0.45 15 25 40 37.5% -
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