基于机器学习的燃煤锅炉燃烧效率在线计算

Online calculation of coal-fired boiler combustion efficiency based on machine learning

经济发展方向与政策导向促使火电厂燃煤锅炉朝着智能化方向升级,燃煤锅炉的燃烧效率是衡量锅炉运行状况的重要指标。为了满足实时计算锅炉热效率的要求,借助于电厂的日常测量数据计算锅炉效率,计算方法为:①分析锅炉的燃烧运行特征;②根据提取的特征采用剔除异常数据、稳态判别、相似性处理的预处理方法,生成更好的训练样本;③采用遗传算法改进的神经网络算法建立锅炉排烟温度、飞灰含碳量和煤质灰分之间的计算模型;利用燃煤热值与理论空气量的比例关系计算入炉煤热值,计算值用于锅炉热效率的反平衡计算模型。计算结果表明,神经网络模型的预测值能满足工程计算的要求;计算所得的排烟温度、飞灰含碳量与煤质灰分用于锅炉效率的计算过程,可实现实时动态的锅炉效率计算;计算所得锅炉效率的变化与实际蒸发量变化基本一致。锅炉实际蒸发量下降时,锅炉效率降低;锅炉实际蒸发量保持60%以上额定蒸发量时,锅炉效率易保持在较高水平。

The direction of economic development and policy orientation has promoted the upgrading of coal-fired boilers in thermal power plants towards the direction of intelligence.The combustion efficiency of coal-fired boiler is an important indicator to measure the operating status of boiler.In order to meet the requirements of real-time calculation of boiler thermal efficiency,the following methods are used to calculate the boiler efficiency with the help of the daily measurement data of the power plant:Firstly,the corresponding combustion and operation characteristics of the boiler were analyzed;Secondly,according to the extracted features,the preprocessing methods of eliminating outliers,steady state discrimination,and similarity processing were carried out to generate better training samples.Finally,the neural network algorithm improved by genetic algorithm was used to establish the calculation model among the boiler exhaust temperature,fly ash carbon content and coal ash content.The calorific value of the coal into the furnace was calculated by using the proportional relationship between the calorific value of coal and the theoretical air volume,and the calculated value was used in the inverse balance calculation model of the boiler thermal efficiency.The calculation results show that the predicted value of the neural network model can meet the requirements of engineering calculation.The calculated exhaust gas temperature,fly ash carbon content and coal ash content can be used in the calculation of boiler efficiency to realize real-time dynamic boiler efficiency calculation.The change of the calculated boiler efficiency is approximately the same as that of the actual evaporation change.When the actual evaporation capacity of the boiler decreases,the efficiency of the boiler will decrease.When the actual evaporation capacity of the boiler is maintained above 60%of the rated evaporation capacity,the boiler efficiency is easily maintained at a high level.