【作者】 杨光军；

【导师】 刘吉臻；

【作者基本信息】 华北电力大学（北京） ， 热能工程， 2008， 博士

【摘要】 随着市场竞争的加剧、能源的日益短缺以及对环境保护的要求越来越严格,迫切需要火电机组提高其锅炉燃烧系统的运行水平,以尽快达到节能减排指标。本文采用基于数据驱动的多种不同方法研究了电站锅炉燃烧的状态监测和性能评价问题,并以此为基础从稳定、经济和环保三个不同侧面统计挖掘锅炉最佳的风煤分配组合,作为优化运行的操作指导。本文的研究内容及取得的主要成果体现在以下五个方面:①通过广泛的选择和比较,在机理分析的基础上,分别选用火焰强度、炉膛压力和蒸汽热能参数三种方式实现燃烧状态的稳定性监测。研究表明,火焰强度和炉膛压力对燃烧状态变化的响应灵敏,可用作稳定性的实时监测;蒸汽热能参数能够从整体上反映稳定性能的高低;并且在同一工况下,稳定性能与经济性能具有一致性。②通过主成分分析法,结合蒸汽热能品质的波动特性,定义燃烧综合稳定因子,作为燃烧稳定性能的评价指标,弥补以往炉内直接监测在全面定量评价燃烧稳定性方面上的不足。计算该性能因子,一方面有助于评判最优燃烧过程,供优化运行参考;另一方面可作为班组考核指标,以促进运行操作水平的提高。③选用烟气含氧量作为燃烧经济性监测参数,并确定锅炉效率为相应的评价指标。借助灰箱建模方法实现烟气含氧量的软测量,以保证过量空气系数的有效估计,从而有助于锅炉效率的计算。研究表明,灰箱模型相比神经网络等辨识模型,具有更加明显的物理意义和更高的预测精度。④以NOx排放量作为燃烧环保性能主要监测和评判参数。根据分级燃烧思想,分别从燃料分级和风分级两种方法入手,通过对某600MW锅炉历史燃烧工况的分析,得出低NOx排放的配风方式以及磨煤机组合方式。⑤综合本文的研究成果,以大唐盘山#3锅炉系统为例,分别以燃烧稳定性能、燃烧经济性能及环保性能为目标,统计分析得到不同负荷区间最佳的磨煤机组合方式和一次风搭配方式,并根据决策树理论挖掘同类工况的风煤最佳出力规则。结果表明,本文所提出的燃烧优化解决方案具有重大的实际应用价值。更多还原

【Abstract】 With the increasing competition from the power market, the shortage of energy, and the severe requirement on environment protection, it is urgent for the thermal power units to improve the operation level of the boiler combustion system, and to meet the requirements on energy saving and emission reduction. This dissertation studies the state monitoring and the performance assessment of the boiler combustion in thermal power units via different data-driven methods, and the best combination mode and load dispatch of the air and fuel for the boiler from the viewpoints of stability, economy and environment are obtained based on the proposed methods. The result can be used as guidance for optimal operation.The main contributions of this dissertation are summarized as follows:1) By extensive selection and comparison, the flame intensity, furnace pressure and steam heat-parameters are used to realize the state monitoring of the combustion stability. It is found that the flame intensity and furnace pressure are sensitive to the change of combustion state, and they can be used as real-time monitor of the combustion stability. The steam heat-parameters can reflect the quality of stability, which accords with the economy performance at the same operating point.2) To remedy the deficiency of the previous methods, a comprehensive index to evaluate the combustion stability performance is proposed as the evaluation index of combustion stability, which is computed from the steam heat quality using the PCA (Principal Components Analysis) method. The result can not only be helpful to search the best combustion process for optimal operation, but also be used as one assess-index for improving the operation level of the engineers.3) The excess-air coefficient is selected as the main monitoring state of combustion economy, and the boiler efficiency is selected as the assess index. To compute the excess-air coefficient and boiler efficiency accurately, the grey-box modeling method is used in the soft sensing of oxygen content in flue gases. The results show that the grey-box model has clearer physical meaning and more exact forecast precision than other identification models such as neural network.4) The NOx (nitrogen oxides) emission is used as the monitor state and evaluation index of combustion environment. The stage combustion methods are discussed for the NOx emission reduction, which is air-stage and fuel-stage. Some rules of air supply and mill combination mode is found by analyzing the history data in a 600MW boiler.5) Taking the NO.3 boiler of Datang Panshan Power Plant as an example, this dissertation obtain the best mode of air supply and mill combination by statistical analysis, and mine the best rules of the load dispatch, with the best combustion performance of stability, economy and environment as separate objective, The result shows that this scheme for combustion optimization is significant in real application.更多还原