基于典型样本数据融合方法的锅炉制粉系统故障诊断

针对D-S证据理论应用中证据对目标模式的信度函数分配难以确定的问题,提出一种基于典型样本的信度函数分配获取方法,利用证据与各个目标模式典型样本之问的汉明距离构造信度函数分配。满足信度函数分配的定义并且减少了其主观性。将此数据融合方法应用到锅炉制粉系统故障诊断中,用以识别磨内煤粉自燃、磨满煤和磨断煤故障,根据历史数据验证,该方法可以有效判别故障类型并且能够做出早期诊断故障预测。     

应用D-S证据理论进行锅炉空气预热器在线故障分析

将数据融合中的D-S证据理论应用到空气预热器故障诊断领域.利用隶属度函数的概念产生各个证据信号对识别模式的信度函数分配,并通过该理论对信度函数进行融合,然后结合目标模式的判定规则对设备运行状态进行判别;结果表明D-S证据理论能有效地进行冗余信息的处理与融合,应用到空气预热器故障分析方面时,能得到较为准确的结果.     

基于锅炉火检信号滤波的燃烧特征提取方法研究

通过滤波方法对电站锅炉传统的火检信号进行了燃烧扰动分析,从中提取除反映火焰有/无之外,更多反映燃烧特征的信息.对某600 MW机组24支煤火检和16支油火检输出信号进行了滤波分析,结果表明:单火检燃烧强度与本层燃烧器燃料量信号中频带存在明显的相关性,且火检平均强度信号与总燃料量信号中频带也存在明显的相关性.经过滤波后的火检信号能够快速反映锅炉燃烧状态的变化,并验证了利用CCD摄像机获取火焰信息的可行性.说明火检信号可用于控制系统前馈及燃烧故障的诊断.     

采用数据融合方法诊断电站锅炉的燃烧稳定性

电站锅炉燃烧稳定性易受锅炉负荷、煤质等因素影响,单一的火检信号或炉膛压力信号所反映的燃烧状态信息,既不准确也不完整.为提高对炉内燃烧状态的判别质量,引入了数据融合的方法.通过采用D-S证据理论方法对常规火检信号和炉膛压力压信号进行融合,得到综合诊断结果,并提出了一种简单可行的基本概率分配方法.对某电厂监控信息系统中保存的某一时间段的运行数据进行分析验证.结果表明:基于证据理论融合后的诊断结果较各传感器单独决策的结果精度高、可靠性强,不确定性大大减小,从而能对燃烧状态作出更有效的诊断.     

330MW锅炉燃烧优化的试验研究

根据330 MW锅炉的试验数据,重点探讨了中速磨煤机工作特性与旋流燃烧器的匹配性及其对燃烧稳定性、火焰温度分布和锅炉效率的影响.通过优化调整磨煤机挡板开度、一次风压和输粉管煤粉分配均匀性以及煤粉细度,改善了单只燃烧器出口的燃烧条件,增强了燃烧稳定性,使着火条件较差的A层燃烧器出口着火区火焰温度上升40 K,A、B层燃烧器出口火焰平均温度提高70 K,火焰温度分布均匀性随之提高.在此基础上,进一步调整二次风控制方式和过氧量,降低了飞灰和灰渣可燃物含量.该优化调整方案可使锅炉效率提高1.8%.     

一种基于自适应小波变换的火焰检测方法的研究

1引言锅炉煤粉燃烧已成为工业生产和人民生活所必须的一种能量和动力来源,而火焰检测系统是保障锅炉安全运行的关键所在。为避免炉膛爆燃事故的发生,火检系统必须能对炉膛的燃烧状况进行实时准确的判别。由于可见光波动强度较小,频谱范围较窄,利用单燃烧器检测可见光信号比依靠     

基于功率谱的一种新型燃烧器燃烧状况识别

为有效地对新型燃烧器火焰燃烧状况进行识别,通过光电传感器获得一系列火焰光强信号,然后利用快速傅里叶变换(FFT)对火焰光强信号采样时间序列进行分析得出功率谱曲线,判断出非接触式的辐射式燃烧器燃烧状况稳定,进而得出了该种燃烧器燃烧孔开口大小及位置合理的结论.应用结果表明,燃烧火焰时域信号的采样频率至少要1 000 Hz,稳定的火焰信号功率谱低频部分波动小,不稳定的火焰信号功率谱波动相对于稳定的要大很多.     

低负荷燃烧器摆角上摆受限于火检检测的探析

浙能阿克苏热电超临界锅炉自投产以来,再热器汽温一直低于设计值,其控制以调节燃烧器喷嘴摆动角为主,事故喷水减温为辅。当燃烧器摆角上摆至75%～80%时,磨煤机火检强度信号开始出现脉动,严重时造成磨煤机失去火检信号而跳磨。对大型煤粉锅炉来说,炉膛燃烧火焰的稳定是保证锅炉安全和经济运行的重要条件,因此炉膛火焰有效和可靠的检测极为重要,是炉膛安全监视系统（FSSS/BMS）的“眼睛”,其安装位置与角度决定了最佳火焰范围的可靠性与准确性。     

基于LS-SVM的燃烧状况智能诊断

运用D-S证据理论以及多传感器信息融合理论建立了数据融合目标识别系统,将其应用于燃烧状况诊断系统中,并利用最小二乘支持向量机理论以及自适应遗传算法理论解决了D-S证据理论当中基本概率分配函数难以获取的问题.所建立的燃烧诊断系统取得了比常用的燃烧状况诊断系统更高的燃烧状况诊断准确率,其中稳定燃烧诊断正确率为84%,不稳定燃烧诊断准确率为79%.     

基于OH-PLIF测量技术的煤粉射流火焰着火燃烧特性

在光学诊断型煤粉燃烧器系统上研究煤粉着火燃烧特性,利用ICMOS相机捕捉射流火焰总光强信号、自发辐射信号以及PLIF荧光信号,根据获得信号的品质,判断各种测试手段的优缺点.计算射流火焰总光强和PLIF荧光信号的着火延迟时间,分析PLIF测量手段的可靠性,结合OH-PLIF技术的瞬态图像,以及着火延迟时间的变化规律,分析射流火焰挥发分着火及燃烧特性.研究结果表明,颗粒群着火是挥发分先析出着火燃烧,然后加热焦炭颗粒燃烧的过程.     

某电厂220t/h锅炉煤粉燃烧器改造设计方案

为提高某电厂220t/h煤粉锅炉燃烧器低负荷稳燃能力，拟采用浓淡燃烧技术对该炉燃烧器进行改造；下层燃烧器采用水平浓淡燃烧器，上层燃烧器采用上下浓淡燃烧器；为保证低负荷时的主蒸汽温度，上层燃烧器为摆动式燃烧器。     

Characteristics of flame stability and gaseous emission of biocrude-oil/ethanol blends in a pilot-scale spray burner

A burner system with capacity of 30,000 kcal/h was designed for the combustion of biocrude-oil and ethanol blends. An air atomizing spray nozzle with larger fuel orifice was adopted to prevent nozzle clogging, with swirl flow introduced to the combustion air for flame stabilization. Biocrude-oil was prepared from the fast pyrolysis of woody biomass and was blended with ethanol to improve flame stability and ignition characteristics. At various mixing ratios of biocrude-oil and ethanol, flame stability was determined, and gaseous emissions of CO and NO were measured. It was found that stable combustion could be achieved with up to 90 vol% of biocrude-oil. CO emissions of biocrude-oil/ethanol blends were smaller than those of pure ethanol, whereas CO concentration increased significantly in case of pure biocrude-oil due to incomplete combustion. Pollutant NO emission increased slightly with the biocrude-oil mixing ratio. The biocrude-oil burner in this study could provide a design database for industrial burner development.     

Mechanism analysis on the pulverized coal combustion flame stability and NOx emission in a swirl burner with deep air staging

Low NOx burner and air staged combustion are widely applied to control NOx emission in coal-fired power plants. The gas-solid two-phase flow, pulverized coal combustion and NOx emission characteristics of a single low NOx swirl burner in an existing coal-fired boiler was numerically simulated to analyze the mechanisms of flame stability and in-flame NOx reduction. And the detailed NOx formation and reduction model under fuel rich conditions was employed to optimize NOx emissions for the low NOx burner with air staged combustion of different burner stoichiometric ratios. The results show that the specially-designed swirl burner structures including the pulverized coal concentrator, flame stabilizing ring and baffle plate create an ignition region of high gas temperature, proper oxygen concentration and high pulverized coal concentration near the annular recirculation zone at the burner outlet for flame stability. At the same time, the annular recirculation zone is generated between the primary and secondary air jets to promote the rapid ignition and combustion of pulverized coal particles to consume oxygen, and then a reducing region is formed as fuel-rich environment to contribute to in-flame NO_X reduction. Moreover, the NOx concentration at the outlet of the combustion chamber is greatly reduced when the deep air staged combustion with the burner stoichiometric ratio of 0.75 is adopted, and the CO concentration at the outlet of the combustion chamber can be maintained simultaneously at a low level through the over-fired air injection of high velocity to enhance the mixing of the fresh air with the flue gas, which can provide the optimal solution for lower NOx emission in the existing coal-fired boilers.     

煤粉浓缩燃烧技术的应用及其利弊分析

分析了煤粉浓度对着火热、火焰的传播速度、燃烧强度、燃烧时间和NOx 排放的影响 ,总结了煤粉浓缩燃烧的优势及应用 ,分析了某些浓淡燃烧器可能发生的问题     

THE INFLUENCE OF MOISTURE ON THE COMBUSTION OF WOOD

A new three-dimensional (3-D) field model for enclosure fire growth has been developed by CSIRO and UNSW, Australia. The model includes the coupling of gas-phase combustion and the pyrolysis of wood. It has been used to predict the flame spread and fire development in a room witha rear timber wall and a propane burner. A parametric study of the effects of the moisture content of the timber on the flame spread and development of the fire in a room is described. The computed results compare satisfactorily with measurements from a fire test carefully conducted in a room.     

天然气在渐变型多孔介质中的预混燃烧

设计了孔径沿程变化的渐变型多孔介质(GVPM)燃烧器，为了解天然气在其中的预混燃烧特性，对燃烧室气体、固体温度分布和CO、NO；污染物排放进行了测量．试验研究了渐变型多孔介质中燃烧的温度场分布、火焰移动、污染物排放、稳定性及多孔介质孔径结构对燃烧特性的影响规律．将研究结果与几种均匀型多孔介质(HPM)中的燃烧进行比较，发现渐变型多孔介质中的燃烧可以有更多的优点，包括均匀温度场分布、极低污染物排放、高火焰速度、高稳定性、宽燃烧极限和有很大的负荷调节范围等．     

采用发射光谱法检测煤粉锅炉火焰的技术研究

利用以CCD阵列作为光电接收元件的微型光纤光谱仪,在燃煤锅炉现场测量火焰从533nm至1050nm波段的发射光谱。通过对不同工况的在大量实测数据曲线进行分析处理,得到了视场中火焰平均温度和黑度。并发现：（1）煤粉火焰辐射基本上可以作为灰体辐射处理;（2）煤粉燃烧器负荷增大时,火焰黑度相应增大,火焰温度波动减小;（3）炉膛内背景火焰燃烧稳定,黑度远大于燃烧器出口火焰黑度,火焰温度波动明显降低;（4）未着火煤粉的温度较低,波动很小,黑度也很小。火焰发射光谱的这些特征为进行火焰监测和诊断提供了可靠的判据。图6表1参9     

Increasing the efficiency of radiant burners by using polymer membranes

Gas-fired radiant burners are used to convert fuel chemical energy into radiation energy for various applications. The radiation output of a radiant burner largely depends on the temperature of the combustion flame. In fact, the radiation output and, thus, the radiant efficiency increase to a great extent with flame temperature. Oxygen-enriched combustion can increase the flame temperature without increasing fuel cost. However, it has not been widely applied because of the high cost of oxygen production. In the present work, oxygen-enriched combustion of natural gas in porous radiant burners was studied. The oxygen-enriched air was produced passively, using polymer membranes. The membranes were shown to be an effective means of obtaining an oxygen-enriched environment for gas combustion in the radiant burners. Two different porous radiant burners were used in this study. One is a reticulated ceramic burner and the other is a ceramic fibre burner. The experimental results showed that the radiation output and the radiant efficiency of these burners increased markedly with rising oxygen concentrations in the combustion air. Also investigated were the effects of oxygen enrichment on combustion mode, and flame stability on the porous media.