高级检索

    基于KEE-PINN算法的锅炉屏过壁温预测方法

    Forecasting method for platen superheater tube temperature distributions in coal fired boiler based on KEE-PINN model

    • 摘要: 准确预测金属管屏的温度分布对防止管壁超温和保障燃煤锅炉安全运行具有重要意义。由于测量手段受限且数值模拟方法耗时较长,为此常采用人工神经网络方法实现管屏壁温分布的快速预测。然而人工神经网络方法可解释性差,且对样本数据依赖性过高,泛化能力差。为此,将数据挖掘算法与物理信息神经网络算法相结合,提出一种预测燃煤锅炉屏过壁温分布的KEE–PINN(Knowledge Extraction and Embedding – Physical Informed Neural Network)算法。模型首先通过FP–Growth算法分析锅炉历史运行数据,得到各运行参数与管屏温度的关联规则及其置信度,并以此为影响因素建立CFD典型工况数据库。随后,构建转置卷积神经网络模型,以锅炉各项运行参数及管屏编号为输入,以管屏温度分布为输出,并将数据挖掘得到的关联规则及其对应置信度嵌入到神经网络结构中,促使模型服从先验物理规律约束。以某600 MW超临界墙式对冲燃烧锅炉屏式过热器为研究对象,预测结果与实测值及计算值吻合良好。结果表明KEE–PINN模型在未知工况下依靠模型内置的先验物理规律,仍可实现锅炉管屏温度分布的准确预测,MSE仅为0.023,满足电厂的实际需求。此外,模型以关联规则的置信度作为各物理损失项的权重,不再因缺乏依据而采用自适应算法获取损失权重,使其具有较强的可解释性和统计数据依靠,解决了传统PINN模型中无法平衡各物理损失项的缺点。

       

      Abstract: Overheating and the resultant tube failures of boiler high temperature heating surfaces such as platen superheater is one of the sore major problems affecting safe operation of coal-fired power generating units. Accurate prediction of metal tube temperature distribution improves operation safety and reduces the risk of tube-overheating. Due to the limitation of measurement method and the huge time cost of numerical method, artificial neural network was used to predict the tube temperature distribution. However, the traditional artificial neural network methods lack interpretability and overly rely on training samples, leading to poor generalization ability under insufficient data scenarios. Therefore, this paper proposed a novel KEE-PINN (Knowledge Extraction and Embedding – Physical Informed Neural Network) method for platen superheater tube temperature distribution, which integrates the data mining algorithms with physical informed neural networks. Firstly, in order to find out the boiler operating parameters that affect the tube temperature distribution of the platen superheater, a data mining model based on association rules was established to analyze the historical operating data of boiler. And, a CFD typical operating condition database was established based on the obtained association rules. Subsequently, a deconvolution neural network that uses the boiler operating parameters as the input and the platen superheater tube distribution as the output was constructed. And, the monotonic relationships obtained by the data-mining model were embedded into the deconvolution neural network model, prompting the model to obey the mechanisms and effectively inhibiting the overfitting or underfitting issues. Taking platen superheater of a 600 MW super-critical wall-fired boiler, the results shows that the KEE-PINN model can maintains adherence to the verified monotonic physical relationship between parameters even in unknown operating conditions, and can realize the real-time prediction of tube temperature distribution. The MSE error of PINN model is only 0.023. Both the accuracy and the response speed of the model meet the demand of coal-fired plants for real-time monitoring of tube temperature distribution. In addition, the model adopts the confidence of the association rules as the weights of physical loss terms, instead of obtaining it from adaptive algorithms due to the lack of physical interpretation. This makes the weights of physical loss highly interpretable and statistically dependent, and solves the drawback of not being able to balance each physical loss term in traditional PINN models.

       

    /

    返回文章
    返回