交叉筛透筛率影响因素及其智能预测模型研究

Study on the influencing factors of cross screening rate and its intelligent prediction model

  • 摘要: 湿黏细粒原煤的干法深度筛分是实现煤炭高效洁净利用的关键技术之一。交叉式细粒滚轴筛(交叉筛)是一种新型干法深度筛分设备,有效解决了传统干法筛分设备易出现“筛面堵孔”等问题。针对筛分过程的数学模型和DEM(Discrete Element Method)模型均存在难以准确预测实际筛分性能的问题,基于机器学习方法对交叉筛的透筛率智能预测模型进行了研究。利用斯皮尔曼相关系数矩阵热力图分析了给料率、外水含量、筛面倾角和筛轴转速4个特征变量与透筛率之间及各特征之间的相关性,分别基于线性回归(Linear Regression, LR)、支持向量机(Support Vector Machine, SVM)、决策树(Decision Tree, DT)和随机森林(Random Forest, RF)算法建立了4种交叉筛透筛率智能预测模型,并结合粒子群算法(Particle Swarm Optimization, PSO)对支持向量机、决策树及随机森林3种模型进行超参数组合优化,得到模型的最佳参数组合并提高了模型的预测性能和泛化能力。利用拟合决定系数R2(Coefficient of Determination)、均方误差EMS(Mean Square Error)和平均绝对误差EMA(Mean Absolute Error)3个评价指标,比较了各模型的预测性能。其中,PSO-SVM预测模型性能最好,对数据的拟合能力最强,其评价指标R2达到了0.976 1,且预测的结果与实际值的误差最小,相应的评价指标EMSEMA分别为3.110×10−4和1.353×10−2。LR模型的预测性能最差,其评价指标R2仅为0.722 2,且预测的结果与实际值的误差最大,EMSEMA分别为1.320×10−3和3.137×10−2。此外,相比于LR模型,添加L1和L2正则化获得的模型预测准确率分别提高了20.26%和4.43%。研究结果为建立交叉筛的透筛率机器学习智能预测模型提供了参考,为分析交叉筛的特征变量对透筛率的影响机理提供了新方法,为实现交叉筛的智能化控制及结构优化提供了理论依据。

     

    Abstract: The dry deep screening of wet viscous fine-grained raw coal is one of the key technologies to realize the efficient and clean utilization of coal. Cross-type fine-grained roller screen (cross screen) is a new type of dry deep screening equipment, which effectively solves the problems of screen surface plugging and other problems that are easy to occur in traditional dry screening equipment. The mathematical model of the screening process and the DEM (Discrete Element Method) model are difficult to accurately predict the actual screening performance. Based on the machine learning method, the intelligent prediction model of the screening rate of the cross screen is studied. The Spearman correlation coefficient matrix heat map was used to analyze the correlation between the four characteristic variables of feed rate, external water content, sieve surface inclination and sieve shaft speed and the screening rate and the correlation between the characteristics. Based on linear regression (LR), support vector machine (SVM), decision tree (DT) and random forest (RF) algorithms, four intelligent prediction models of cross screening rate were established. Combined with particle swarm optimization (PSO), the hyper-parameter combination optimization of support vector machine, decision tree and random forest models is carried out to obtain the optimal parameter combination of the model and improve the prediction performance and generalization ability of the model. The prediction performance of each model was compared by using three evaluation indexes coefficient of determination (R2), mean square error (EMS) and mean absolute error (EMA). Among them, the PSO-SVM prediction model has the best performance and the strongest fitting ability to the data. Its evaluation index R2 reaches 0.976 1, and the error between the predicted result and the actual value is the smallest. The corresponding evaluation indexes EMS and EMA are 3.110×10−4 and 1.353×10−2. The prediction performance of the LR model is the worst, and its evaluation index R2 is only 0.722 2, and the error between the predicted result and the actual value is the largest, EMS and EMA are 1.320×10−3 and 3.137×10−2. In addition, compared with the LR model, the prediction accuracy of the model obtained by adding L1 and L2 regularization is increased by 20.26 % and 4.43 %, respectively. The research results provide a reference for the establishment of the machine learning intelligent prediction model of the screening rate of the cross screen. It provides a new method for analyzing the influence mechanism of the characteristic variables of the cross screen on the screening rate, and provides a theoretical basis for realizing the intelligent control and structural optimization of the cross screen.

     

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