大容量电站锅炉的可靠性统计和分析

介绍了大容量电站锅炉可靠性统计与可靠性分析使用的术语定义、锅炉及锅炉部件可靠性特征量的计算公式、锅炉可靠性薄弱环节的统计方法和锅炉部件的可靠性统计方法。给出了大容量电站锅炉22个可靠性常用术语、12个可靠性统计的时间定义、12个可靠性特征量的计算公式和某型号600MW锅炉可靠性的统计结果。这些可靠性术语定义、可靠性特征量的计算公式和可靠性统计方法为大容量锅炉的可靠性分析、可靠性评定、可靠性设计与可靠性管理提供了依据。     

大容量电站锅炉系统可用性的设计方法

提出了大容量电站锅炉系统可用性的设计方法,包括评价电站锅炉可用性的特征量、零部件及子系统的可用度计算模型以及锅炉系统可用系数的计算模型.应用该设计方法,对某型号超临界600 MW锅炉子系统的可用度及锅炉系统的可用系数进行了预测.结果表明:该设计方法可在设计阶段定量地确定电站锅炉的零部件、子系统和系统的可用性特征量,为大容量电站锅炉可用性的设计、分析和改进提供了科学依据.     

钢构架的计算与设计

电站锅炉是火力发电三大动力支柱之一，在国民经济的发展中起着举足轻重的作用。锅炉钢构架是电站锅炉的主要承重部件，它约占整台锅炉重量的１／３，构架的形式由锅炉的容量、各部件的布置及其支承形式来决定。在钢构架日增的今天，构架的使用显向越来越重要。计算与设计的合理性，直接影响到锅炉的安全、经济性和运行、检修的方便性。本文的计算采用有限元计算法。     

大容量电站锅炉受热面管子的可靠性设计与寿命评定

以传统的设计方法为基础，提出了大容量电站锅炉受热面管子的振动和强度可靠性设计方法以及寿命的评定方法。在振动可靠性设计方面，把卡门漩涡频率和声学驻波频率处理为随机变量，使用概率设计法确定锅炉尾部受热面振动设计的可靠度。在强度可靠性设计方面，把锅炉受热面管子的外径、壁厚、管内压力、材料强度等设计量根据实际处理为随机变量，使用可靠性分析技术确定锅炉受热面管子强度设计的可靠度。在寿命评定方面，对锅炉受热面管子的寿命数据进行统计分析，确定锅炉受热面管子的平均寿命。通过对锅炉受热面管子壁厚的监测和跟踪，确定锅炉受热面管子的剩余寿命。给出了水冷壁、过热器、再热器和省煤器管子强度可靠性设计的实例、管式空气预热器管束振动的可靠性设计实例和锅炉过热器管子寿命评定的实例。表1参9     

基于CCD图像的高温蒸汽管道位移测量系统研究

高温蒸汽管道是电站锅炉的核心承压部件,长期处于高温、高压、蠕变、疲劳等恶劣运行环境下。实时监测电站锅炉蒸汽管道的宏观位移并对其安全进行评估,可提高机组运行的安全性和稳定性。本文提出一种基于CCD图像的非接触式高温蒸汽管道位移测量方法,采用直接线性法,利用棋盘格标定板对CCD相机进行标定,标定好的CCD相机获取被测管道上圆形标志物的一系列图像,采用改进的搜索路径SSDA法对采集到的图像进行相关计算,即可实现位移测量。在实验室条件下,设计并搭建了图像位移测量系统,对测量方法进行了验证及性能评价。结果表明:系统相对误差小于0.5%,零点漂移小于0.1 mm,重复性优于0.08%。     

大容量直流锅炉在线寿命监测系统

本文针对某厂捷制200MW直流锅炉主要承压高温部件的寿命在线监测,通过有限元分析计算,获得了各控制部件的应力集中系数,比较各寿命规范,结合该炉的具体情况,提出了适合计算机寿命在线监测方法.对监测部件的内外壁温差按不同的温升速度,不同的内壁放热系数及采用常物性和变物性等条件下,进行数值计算,解决了在线寿命计算机监测系统遇到的问题,并开发了大容量电站直流锅炉在线寿命监测软件包.     

电站锅炉安装中对承压部件的质量控制

对锅炉承压部件进行有效的产品质量控制,是保证电站锅炉安装安全质量的重要环节。电站锅炉制造单位、安装单位对锅炉承压部件产品质量控制存在的问题,主要体现在分包质量控制不到位,分包单位不具备相应的制造许可资格,分包产品制造过程未按规定申报监督检验,产品到货验收不规范等。     

大型电站锅炉导向装置的应力分析

本文系统介绍了大型电站锅炉导向装置的设计原理，结构特点及大型电站锅炉导向装置在钢结构设计中应力分析的计算方法。对于保障产品在设计使用寿命内安全性和可靠性起着重要作用。     

超临界锅炉寿命损耗在线监测系统研究

采用三维有限元计算对超临界锅炉厚壁部件在内压作用下的应力场进行了分析，并计算出了汽水分离器应力集中系数；采用GB／T9222—88之附录D为汽水分离器寿命损耗在线监测计算标准。对过热器和再热器出口集箱采用ASME-47为在线监测计算标准。开发了适用于超临界锅炉厚壁承压部件寿命在线监测系统。该系统利用计算机、DAS／DCS和MODBUS通讯协议对超临界锅 炉壁承压部件寿命进行管理，并提供开放数据接口。     

锅炉承压部件损伤的原因与对策探究

随着国内供暖需求量的不断增加,对于锅炉供暖质量也提出了更高的要求,但是现阶段锅炉在运行过程中经常性的会发生故障,在很大程度上影响了锅炉供暖质量,对于发电厂来讲,必须要定期的对锅炉进行维修检查,提高锅炉运行安全性和可靠性。本文重点对锅炉承压部件损伤原因进行分析,同时结合具体案例提出承压部件损伤维修对策。     

电站锅炉高温受压元件蠕变和低周疲劳寿命损伤计算及在线监测

高温蠕变和低周疲劳是锅炉高温受压元件寿命损伤的主要机理.采用高温受压元件蠕变和低周疲劳寿命在线监测是提高锅炉安全运行和管理水平的有效途径.给出了电站锅炉高温受压元件蠕变和低周疲劳寿命损伤的计算方法,扼要介绍了寿命损伤在线监测的基本原理、技术关键、使用范围和实际的应用情况.     

电站主设备可靠性定量设计技术的研究

提出了电站主设备可靠性定量设计的方法，介绍了收集现场使用可靠性数据，建立可靠性数据库，分析可靠性薄弱环节和严重的失效模式，确定设计量的分布参数等可靠性设计的基础工作，使用概率设计法和历史数据统计分析法确定关键零件和普通零件的可靠度和可用度；给出了电站主设备的零件，子系统和系统的可靠度，可用度的计算公式和应用于汽轮机产品上的实例，图1参10。     

锅壳式锅炉管板应力有限元分析及优化设计

针对某锅壳式锅炉管板的结构仿真分析和强度计算问题,根据相关的理论和方法建立了有限元仿真模型,并采用通用有限元软件ANSYS Workbench的结构静力分析模块进行应力计算,得到了管板的变形云图和应力云图。在结构分析的基础上,根据相关强度理论和材料标准对模型进行应力结果的评定和分析,结果显示,所有部件满足强度要求并且留有较大的设计余量。在保证强度要求的前提下,对锅炉的锅壳和管板进行结构优化,减少了锅炉的整体重量并降低了材料成本。     

Modeling of Flow System Dynamics

This paper presents non-linear and linear models of flow system of laboratory stand (semi-industrial scale) with pressurized fluidized bed boiler. The non-linear model belongs to the class of lumped parameter models. The linear model was obtained experimentally using a novel method for design of control systems in industrial plants - MIKOZ. This study has connection with comparison of various methods of mathematical modeling of flow systems frequently encountered in power equipment.     

Reliability and availability analysis of low power portable direct methanol fuel cells

This paper presents a methodology for modeling and calculating the reliability and availability of low power portable direct methanol fuel cells (DMFCs). System reliability and availability are critical factors for improving market acceptance and for determining the competitiveness of the low power DMFC. Two techniques have been used for analyzing the system reliability and availability requirements for various system components. Reliability block diagram (RBD) is formed based on the failure rates of irreparable system components. A state-space method is developed to calculate system availability using the Markov model (MM). The state-space method incorporates three different states—operational, derated, and fully faulted states. Since most system components spend their lifetime in performing normal functional task, this research is focused mainly on this operational period. The failure and repair rates for repairable DMFC systems are estimated on the basis of a homogeneous Poisson process (HPP) and exponential distribution. Extensive analytical modeling and simulation study has been performed to verify the effectiveness of the proposed technique.     

Reliability design method for steam turbine blades

Based on theories of probability and statistics, and taking static stresses, dynamic stresses, endurance strength, safety ratios, vibration frequencies and exciting force frequencies of blades as random variables, a reliability design method for steam turbine blades is presented. The purport and calculation method for blade reliability are expounded. The distribution parameters of random variables are determined after analysis and numerical calculation of test data. The fatigue strength and the vibration design reliability of turbine blades are determined with the aid of a probabilistic design method and by interference models for stress distribution and strength distribution. Some blade reliability design calculation formulas for a dynamic stress design method, a safety ratio design method for fatigue strength, and a vibration reliability design method for the first and second types of tuned blades and a packet of blades on a disk connected closely, are given together with some practical examples. With these methods, the design reliability of steam turbine blades can be guaranteed in the design stage. This research may provide some scientific basis for reliability design of steam turbine blades. __________ Translated from Chinese Journal of Applied Mechanics, 2007, 24(3): 331–335 [译自: 应用力学学报]     

A heuristic-based approach for reliability importance assessment of energy producers

Reliability of energy supply is one of the most important issues of service quality. On one hand, customers usually have different expectations for service reliability and price. On the other hand, providing different level of reliability at load points is a challenge for system operators. In order to take reasonable decisions and obviate reliability implementation difficulties, market players need to know impacts of their assets on system and load-point reliabilities. One tool to specify reliability impacts of assets is the criticality or reliability importance measure by which system components can be ranked based on their effect on reliability. Conventional methods for determination of reliability importance are essentially on the basis of risk sensitivity analysis and hence, impose prohibitive calculation burden in large power systems. An approach is proposed in this paper to determine reliability importance of energy producers from perspective of consumers or distribution companies in a composite generation and transmission system. In the presented method, while avoiding immense computational burden, the energy producers are ranked based on their rating, unavailability and impact on power flows in the lines connecting to the considered load points. Study results on the IEEE reliability test system show successful application of the proposed method.