600MW汽轮机旁路泄露热经济性分析

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1、分类号电力高等专科学校毕业设计论文题目 600MW汽轮机旁路泄露热经济性分析并列英文题目600MW steam Turbine bypass leakage of thermal heat economy analysis摘要：本课题通过研究600MW热力发电厂热力系统的设计数据,计算汽轮机组各经济性指标。判断引起汽轮机高低压旁路泄露的原因,指导机组的节能改造。采用等效热降的方法定量分析热力系统能量损耗的变化,以采取有效措施防止高低旁泄露和热经济性的下降,能根据计算结果分析机组高低旁路泄露对电厂经济性的影响,从而指导电厂发现机组存在的缺陷和问题,指出节能改造的途径的措施,提高电厂的运行水平。关

2、键词：高低压旁路,等效热降,热经济性Abstract: in this thesis, through the study of 600MW thermal power plant thermal system design data, calculation of steam turbine unit each economy index.Determine the cause for high and low pressure bypass leakage causes of guidance unit, energy saving.The equivalent enthalpy drop

3、 method for quantitative analysis of thermal energy loss of the system changes, to take effective measures to prevent leakage of high and low side and thermal economic decline, according to the calculation and analysis of the unit or bypass leakage on the economy of power plants influence, thus guid

4、ing the plant found units exist defects and problems, pointed out energy-saving ways measures power plant, improve the operation level of power station.Key words:High and low pressure bypass, equivalent heat drop,thermal economy.目录0.前言11. 汽轮机热力系统级再热蒸汽的旁路系统31.1 600MW机组热力系统31.2再热机组的旁路系统443 / 450.前言以中国

5、电力投资集团公司所属拉西瓦水电站6号机组投产为标志,截止20XX8月末,我国电力装机容量突破11.2亿千瓦。目前,全国30万千瓦及以上的大火电机组的比重已达62,60万千瓦及以上的清洁高效机组成为新建项目的主力机型。但是,受火电新增规模下降、新增装机区域分布不平衡、电源电网建设不协调等因素影响,考虑气候、来水、电煤供应等条件,全国电力供需偏紧态势仍将持续,部分地区面临不同程度的电力缺口。特别是南方、华中等水电比重较大的区域,以及一些火电上网电价偏低的产煤省区,将会出现持续性缺电现象。电力行业是国民经济的重要支柱行业,是国家经济发展战略中的重点和现行行业。是关系国计民生的基础产业,是世界各国经济

6、发展战略中的优先发展重点。因此我国早在20世纪50年代初就确定了电力行业先行的地位。随着我国经济的发展,对于电力的需求量不断的增大,肯定刺激电力行业的发展。同时人们生活水平的提高,对电力的的需求量也日益增加。但是随着煤电关系的日益严峻,火电厂的节能降耗已成为必须采取的措施。随着电厂由生产型向经营型的转变,改善电厂运行机组的经济性能,对提高全厂的经济效益至关重要。对于运行时间长的机组,长时间在高温高压的工况下机组零部件跑、冒、滴、漏的情况时有发生时。随着机组容量与参数的不断提高,使得凝汽式汽轮机组热力系统得组成日趋复杂,系统中局部因素对机组热经济性的影响越来越受到人们的重视。尤其是要正确认识汽轮

7、机旁路系统中的阀门漏因素对机组安全和经济性的影响。汽轮机旁路系统中的阀门漏对机组安全性的影响很大,很多学者都已经做很深的研究,但对于汽轮机旁路系统中的阀门漏对机组经济性影响的研究很少,本文就是从汽轮机旁路系统中的阀门漏对经济性的影响方面做一些研究。等效热降法是一种新的热工基础。早在六十年代后期,它首先由库兹湟佐夫提出,并在七十年代逐步完善、成熟,形成了完善的理论体系。等效热降法既可用于整体热力系统的计算,也可用于热力系统的局部分析定量计算。它基本上属于能量转化热平衡法。但是它摈弃了繁杂的常规计算的缺点,不需要全盘重新计算就能查明系统变化的经济性,即用简捷的局部运算代替整个系统的复杂计算。等效热

8、降法主要用来分析蒸汽动力装置和热力系统。在火电厂的设计中,用以论证方案的技术经济性,探讨热力系统和设备中各种因素的影响以及局部变动后的经济效益,是热力工程和热系统优化设计的有利工具。对于运行电厂,可用等效热降法分析技术改造,分析热系统节能技术改造,可为改造提供确切的技术依据。考虑各种引进型机组结构与系统型式不一,本文主要论述沁北电厂哈汽利用日本三菱公司技术制造开发的引进型600MW机组,着眼点主要在于汽轮机旁路系统两级串联旁路系统。通过分析运行工况及暴露出来的问题,分析其对电厂的安全和经济性的影响。可以为提高机组整体的经济性提供科学依据,据此来改善机组的运行状况,降低发电成本,并使全厂安全、可

9、靠、经济的运行。1. 汽轮机热力系统级再热蒸汽的旁路系统沁北电厂#1,#2机汽轮发电机采用汽轮机厂XX公司引进日本三菱公司技术制造的CLN60024.2/566/566型汽轮发电机回热系统为三高、四低、一滑压除氧。各高低压加热器均有疏水冷却段。加热器的疏水采用逐级自流,不设疏水泵。1.1 600MW机组热力系统图：超临界600MW机组原则性热力系统该机组汽轮机由瑞士ABB公司提供,为单轴四缸、四排汽、反动、凝汽式汽轮机。配有八级不调整抽汽,回热系统为三高、四低、一滑压除氧。高压加热器H1、H3和低压加热器H5设有蒸汽冷却段,各回热加热器均设有均有疏水冷却段。疏水采用逐级自流方式,高加加热器的疏

10、水逐级自流进入除氧器,低压加热器疏水逐级自流流入凝汽器热井,轴封加热器的疏水也流入凝汽器热井。系统设有汽动给水泵,小汽机为双流式,其正常工作汽源为第四级抽汽,排气进入主凝汽器。1.2再热机组的旁路系统汽轮机的旁路系统是指高参数蒸汽不进入汽轮机,经过与汽轮机并联的减温减压器,进入再热器或直接排入凝汽器的连接系统中。汽机旁路形式有多种：高压旁路串联低压旁路；再并联大旁路的三级旁路；高、低压两级串联旁路；一级大旁路等。具体采用型式要根据机组的需要而定。现在一般都采用高低压两级串联的形式。高低压旁路站一般均装有减压阀和喷水阀,由于高旁喷水取自给水母管,所以为了防止喷水阀泄漏,高旁喷水阀前还装有喷水截止

11、阀。汽机旁路阀门,特别是高旁减温减压阀,在材选用和结构等方面都充分考虑了耐温耐压、耐交变应力。新蒸汽绕过汽轮机高压缸的,称为高压旁路；再热后的蒸汽绕过汽轮机的中、低压缸的称为低压旁路.图1两级串联旁路系统图2 汽机旁路系统分布位置和流程图1、高旁减温减压阀 2、高旁喷水阀 3、高旁喷水截止阀4、低旁减压阀5、低旁喷水阀6、地旁减温器7、过热器8、再热器 9、汽机高压缸10、汽机中压缸 11、汽机低压缸 12、发电机 13、凝汽器 14、凝水泵15、低压加热器 16、除氧器 17、给水泵 18、高压加热器 19、锅炉旁路系统的功能: 根据机组运行模式及性能要求,沁北超临界压力机组的旁路系统应具有

12、下列基本功能：1在冷、温、热态启动条件下能使蒸汽温度和金属温度相匹配,缩短机组启动时间；2适应机组的调峰和变压运行；3满足机组中压缸冷、热态启动的要求；4满足锅炉不投油最低稳燃负荷的要求；5根据锅炉再热器的材质、布置位置,满足提供再热器冷却蒸汽的要求。1.3 汽轮机旁路系统泄露的原因分析旁路系统的蒸汽减温减压阀,作为旁路系统的核心部件,长期工作在高温高压条件下,在服役过程中可能会发生蠕变、热疲劳、过热氧化、渗碳、腐蚀等现象,这会使材料性能劣化并缩短使用寿命。在工作时不仅要承受相当大的压,而且由于工况的变化和喷水减温的作用,还要承受在较短时间温度剧烈变化所引起的热冲击和热载荷。阀前蒸汽参数为超高

13、压或亚临界甚至达到超临界参数,因此阀前管道一般设计为低合金钢10CrMo910等,而阀后参数经过阀门后均有很大的降低,管材一般为普通碳钢材料,一般只在阀门出口约58m为低合金材料。经分析,旁路阀漏较大的原因有5点：1阀门密封面所受紧力不够。在安装过程中,出现机械零位和热工零位重合的现象,或热工零位确定后,出现阀门密封面紧力不足,导致阀门漏。2阀座下垫片压缩量过大在运行过程中,可能出现垫片变形过大,这也是导致阀门密封面紧力不足的一个间接原因。3阀座变形。如果阀座下垫片变形量过大,可导致阀座密封面变形,引起阀门漏。4安装工艺出现问题。如：阀座下垫片及阀芯垫片装得不正。5厂家在对阀座、阀芯密封面损坏

14、部分进行补焊时,焊接材料硬度不够或焊后出现变形,致使阀杆、阀芯同轴度超标。2 等效热降概述及其概念2.1 简捷计算热力系统的常规计算的目的,在于确定热力系统各部分蒸汽或水的参数及流量,机组的功率和热经济指标汽耗量、热耗量、热耗率和煤耗率等。热力系统常规系统计算的方法有两种：一是定功率计算,即功率给定后求解汽耗量；另一种是定流量计算,即预先给定或估计蒸汽消耗量,求解功率或逐步逼近给定功率。简捷计算是在改进常规计算的过程中逐步完善形成的。它在计算方法和计算技巧上,对常规计算做了一些改进和加工。首先在原始资料整理上进行改进,把热力系统中繁多的热力参数整理为三类：其一是给水在加热器中的焓升,以表示,按

15、加热器编号有；其二是蒸汽在加热器中的放热量,用表示,按加热器编号有以及其它汽源的放热量等；其三是疏水在加热器中的放热量,用表示,按加热器编号有。1加热器分为两类：一类称疏水自流式加热器,它们属面式加热器,其疏水方式为逐级自流；另一类称汇集式加热器,它们是指混合式加热器或带疏水泵的面式加热器,其疏水汇集于本加热器的进口或出口。在整理原始数据时,根据加热器的类型不同,其加热器的、的计算规定也各不相同。对疏水自流式图1.1： 对汇集式加热器图1.2： 2汇集式加热器中：加热器的热平衡方程为： 加热器的质量方程为： 由以上两式得： 式中 进入加热器的疏水份额。若令 即简捷计算的规定,则： 3简捷计算中

16、1.计算中所用的加热器出口水焓,在带疏水泵的汇集式加热器中,是指混合后的焓值,而不是混合前的焓值。2.为了使整个计算更为简明,计算时把系统的各种附加成分,如轴封蒸汽的利用、抽气加热器、轴封加热器、泵的焓升以及外部热源的利用,分别归入相应的加热器,即把加热器及其附加成份视为一个加热整体。其归并的原则是以相邻两个加热器的水侧出口为界限,凡在此界限的一切附加成份都归并到界限的加热器中。3.附加成份的脚码标注应与加热器一致。经过上述加工处理的计算,简捷计算在本质上与热力系统的常规计算并无区别,但在计算形式和方法上作了一些技巧性的改进,从而收到了简单、明了的效果,并且适宜于用计算机运算。4例:沁北电厂哈

17、汽600MW机组热力系统简捷计算哈汽CLN60024.2/566/566设计工况热力参数如下图：附2 .根据热力参数,按简捷计算方法规定整理原始资料得：图中共八台加热器,其设置如下：汇集式加热器： No.5疏水自流式加热器：No.1、No.2、No.3、No.4、No.6、No.7、No.8(1) 给水在加热器中焓升(2) 疏水在加热器中的放热量(3) 蒸汽在加热器中的放热量加热器级数给水焓升蒸汽放热疏水放热1105.72346.7129.1293.92350.394381.52375.481.64168.22527.15178.82613.9227.86125.42599.5130.1716

18、9.62034.0178.781101936.2各加热器参数D、标准煤耗率：E、全年标准煤耗量年利用小时n=6000：D、标准煤耗率：E、全年标准煤耗量年利用小时n=6000：2.2 等效热降等效热降法是基于热力学的热功转换原理,考虑到设备质量、热力系统结构和参数的特点,经过严密地理论推演,导出几个实际热力参量及等,用以研究热功转换及能量利用程度的一种方法。等效热降法主要用来分析蒸汽动力装置和热力系统。在火电厂的设计中,用以论证方案的技术经济性,探讨热力系统和设备中各种因素的影响以及局部变动后的经济效益,是热力工程和热系统优化设计的有利工具。对于运行电厂,可用等效热降法分析技术改造；用以分析热

19、系统节能技术改造收到的良好效果,可为改造提供确切的技术依据。等效热降对于纯凝汽式汽轮机如图2.1,显然,一公斤新蒸汽的做功就等于它的热降即热降。即 千焦耳/公斤图2.1纯凝汽式机组 图2.2回热汽轮机组 式中 蒸汽进汽轮机的初焓 千焦耳/公斤。汽轮机排汽焓 千焦耳/公斤。对于有回热抽汽的汽轮机如图2.2,一公斤新蒸汽做功 式中 ；抽汽份额；抽汽作功不足系数； r任意抽汽级的编号； Z抽汽级数； 由上看出,回热抽汽的作功不是一公斤新蒸汽的简单热降,它比纯凝汽新蒸汽热降小。但是,它与纯凝汽式汽轮机中的又类似,它们都是一公斤新汽的实际作功。为了有别于纯凝汽热降,故称这个作功为等效热降。等效的数量含意

20、,是指回热抽汽式汽轮机一公斤新蒸汽的作功,等效于公斤新蒸汽直达冷凝器的热降,即等效热降。抽汽等效热降及抽汽效率假设一个纯热量即无工质带入系统进入加热器中,使加热器的抽汽减少一公斤,这一公斤蒸汽称为排挤抽汽。这个排挤抽汽中有一部分作功到汽轮机的出口,另一部分作功到后面各抽汽口再被抽出用以加热给水。由于加热器抽汽减少一公斤,在仅有热量加入而无工质加入时,其疏水也相应减少一公斤。因而使加热器由于疏水带入的热量减少。这个减少的热量应由加热器段抽汽来补偿,其补偿量为式中 即加热器一公斤抽汽的放热量,是排挤加热器一公斤抽汽中分配到加热器中的份额。排挤抽汽继续向后流动的份额只有1-了。这部分蒸汽膨胀作功并凝

21、结后,产生相同数量的水返回1号加热器。1号加热器为了加热这部分水,因而抽汽量应增加由于在和加热器中增加了抽汽份额,并产生了作功不足,故加热器排挤一公斤抽汽返回汽轮机的作功等于这个作功称为抽汽的等效焓降,并用符号表示。抽汽效率。如同一般效率概念一样,是作功与加入热量之比。这里排挤一公斤抽汽,需要加入的热量是,而排挤一公斤抽汽获得的功为。因而,和之比是一个热效率的含义,故称之为抽汽效率。3. 等效热降法的经济性分析3.1 沁北电厂等效热降和抽汽效率的计算各加热器系数加热器级数抽汽系数等效热降抽汽效率10.02890 166.10.070789 20.02774289.96110 0.123372

22、30.02466 397.464132 0.16732540.05127 617.1104120.244194 50.05301 809.1220490.30954908 60.04147952.00676860.36622687770.078391088.3606520.53508389980.056881073.8411590.55455442第二节 高低旁路泄露经济性的影响一变热量的经济指标计算变热量的局部定量,除考虑变热量新蒸汽等效热降变换H外,还要考虑响应的循环吸热量Q的变换。即：式中和有正负之分。当作功增加时。为正值,反之为负；当循环吸热量增加时,为正值,反之为负值。局部变动的经济

23、性相对变化是一公斤新蒸汽的吸热量变化,即循环吸热量变化它包括再热器吸热量的变化和锅炉蒸汽吸热量变化两部分。即=+二.两级串联旁路系统中的高压旁路泄露一仅高压旁路调节阀泄露 漏汽份额1.因为高压旁路泄露的蒸汽未经高压缸做功,2.因为高压旁路泄露的蒸汽绕过汽轮机高压缸直接进入再热蒸汽冷段,再热蒸汽中份额的蒸汽具有的焓值为进入再热蒸汽冷段,导致再热蒸汽冷段在再热器中的吸热量减少,而汽轮机各加热器抽汽份额、各抽汽回热加热器给水流量未发生改变循环吸热量不变3.装置热经济性相对降低为：假如旁路阀1%泄露做功减少循环吸热量减少装置经济性相对下降所以：当高压旁路阀调节阀泄露1%时,系统的经济性降低0.1619

24、%。二仅高压旁路减温水调节阀泄露 从给水泵抽头的热力分析 泄露份额由于不经过高压加热器及其产生的气流不经过汽轮机高压缸,故少做功循环吸热量下降：1. 喷水由给水焓加热到再热冷段蒸汽焓所减少的吸热量2. 喷水份额不经过高加而使循环吸热量增加的部分3. 高压加热器回热抽汽减少,使再热流量加大而增加的再热器吸热量部分装置热经济性相对降低为：假如减温水阀1%泄露做功减少循环吸热量减少装置经济性相对下降所以：高压旁路减温水阀调节阀泄露1%时,系统的经济性降低0.1928%三高压旁路调节阀泄露、高压旁路减温水调节阀动作时。泄露份额综合一,二的情况首先计算出当高压旁路蒸汽泄漏时,高压旁路减温水阀进行喷水减温

25、, 的计算：由热平衡方程式得：做功减少：循环吸热量减少：装置热经济性相对降低为：如果高旁阀泄露1%时,减温水阀相应泄露时的计算做功减少循环吸热量减少所以：高压旁路阀调节阀泄露1%时,减温水阀动作时系统的经济性降低0.20%3两级串联旁路系统中的低压旁路泄露一仅低压旁路调节阀泄露 漏汽份额因为低压旁路泄露的蒸汽未经中低压缸做功：因为凝结水总份额不变,汽轮机各加热器抽汽份额、各抽汽回热加热器给水流量未发生改变,循环吸热量不变。装置热经济性相对降低为：假如旁路阀1%泄露做功减少循环吸热量不变低压旁路引起装置热经济相对降低：所以：当低压旁路阀调节阀泄露1%时,系统的经济性降低0.97361%。二仅低压

26、旁路减温水调节阀泄露 从凝输泵泵抽头的热力分析变热量等效热降法 泄露份额因为低压旁路减温水是从凝结水泵出口抽出进入凝汽器。具有一定焓值的给水经凝汽器放热又经过凝结水泵,成为一定焓值的给水,进入一号低压加热器,给水焓值减少,使回热抽汽增加,故少做功：因为凝结水总份额不变,汽轮机各加热器抽汽份额、各抽汽回热加热器给水流量未发生改变,循环吸热量不变。装置热经济性相对降低为：假如减温水阀1%泄露做功减少循环吸热量不变低压旁路减温水调节阀泄露引起装置热经济相对降低：所以：低压旁路减温水阀调节阀泄露1%时,系统的经济性降低0.00003%三低压旁路调节阀、低压旁路减温水调节阀都泄露 份额分别为首先计算出当

27、低压旁路蒸汽泄漏时,低压旁路减温水阀进行喷水减温, 的计算：由设计参数查焓熵图得到计算出做功减少循环吸热量不变如果低压旁路阀泄露1%时,减温水阀相应泄露时做功减少装置经济性相对变化所以：低压旁路阀调节阀泄露1%时,减温水阀动作时系统的经济性降低0.97362%第五章 结论泄漏量影响旁路阀泄露1%减温阀泄露1%旁路阀泄露1%,减温阀动作对高压旁路的经济性影响下降0.1619%0.1928%0.20%对低压旁路的济性影响 下降0.973610.000030.97362旁路泄露对经济性影响由上表可知：1.在高压和低压旁路中,旁路阀泄露1%,减温阀动作时对机组的经济性影响最大。2.对比高、低压旁路可知

28、,旁路阀泄露1%,低压旁路比高压旁路机组的影响更大；减温阀泄露1%,高压旁路比低压旁路机组的影响更大；旁路阀泄露1%,减温阀动作时,低压旁路比高压旁路机组的影响更大。3.总之,在旁路系统中阀门泄露对经济性的影响很大。致 谢时光荏苒,岁月如梭,大学三年过得飞快。论文的完成标志着我大学三年即将结束,也意味着,新的生活将开始了。本篇论文是在老师的指导下完成,老师提出许多修改意见,对论文质量的提高起到了至关重要的作用。衷心地感谢老师对我的帮助。老师在论文的选题、研究理论、框架结构、数据整理,直至撰写、修改和定稿等各个环节都严格把关,并投入了大量的时间和精力。在随着老师学习的过程中,我不仅掌握了等效热降

29、的研究方法,也领会了许多为人处世的道理 ,令人受益匪浅。在大学学习和生活期间,我得到了动力系各位老师的热心关心和帮助,在此表示深深的感谢!在以后的生活和学习中,我一定牢记在大学里学到的知识和技能,牢记老师们的教诲,在工作中认认真真,兢兢业业,为社会做出自己的一份贡献。参考文献1林万超著. 火电厂热系统定量分析. ：交通大学,1985.2义波等合编. 热力发电厂. ：中国电力,2005.3建刚,雪萍著. 汽轮机设备及运行. ：中国电力,2006.附1： 关于汽轮机的翻译Steam turbine accident and PreventionLarge and medium-sized stea

30、m turbine with high temperature, high pressure, high speed and precise structure complex, clearance small features, especially the start, stop, load changes greatly and changing conditions, static and dynamic part of expansion, contraction caused by differential expansion and changes of clearance va

31、riation, caused by thermal stress and deformation of the thrust change and so on are threatening the safety of steam turbine equipment.If the quality is bad, improper operation, the exception handling of decision-making and undeserved or the emergency treatment is not timely, will cause serious dama

32、ge to the equipment accident, difficult to repair, sometimes leading to equipment, not only affect the enterprise economic benefits, but also caused the system output is reduced, affecting the normal power supply.Bending of steam turbine main shaftSteam turbine in does not have the starting conditio

33、ns start, due to temperature difference between upper and lower cylinder, shaft bending, the existence of temporary cylinder inlet, into the condenser, unit vibration and clearance of small factors, causing a large shaft and a stationary part of friction, will cause the shaft bending.General of main

34、 shaft bending of more than 0.07mm, will not be able to maintain the normal operation of the unit vibration value, must be straight shaft processing.In recent years, accident of main shaft bending of quite frequently, especially 200MW and above the intermediate reheat unit is more outstanding, a rou

35、gh estimate in 20 30 times above.In 1985 the Ministry of water and electricity held prevent 200MW unit of main shaft bending of informal discussion, to have occurred 7 times on accident of main shaft bending are analyzed.Analysis shows that: 7 second accident of main shaft bending occurred during st

36、art-up, which is 5 times the hot start occurred 7 times; accident of main shaft bending, most of the stopping or starting in the cylinder inlet, mostly in first order critical speed of the unit vibration, leadership and relevant personnel to perform standard strictly, to speed up the critical, or ev

37、en forced to start several times.7 times in the high pressure rotor shaft bending front steam seal.An informal discussion in analysis of 7 second accident of main shaft bending technology based on reason, developed on the prevention of main shaft bending of 200 MW unit technical measures of this mea

38、sure for the other capacity also can consult carry out.Through the measure carry out fulfil, frequent accident of main shaft bending of the situation to get the degree of control.But because of personnel changes ceaselessly, new staff of the measures the master degree, leadership decision-making, eq

39、uipment and other factors, accident of main shaft bending still occur from time to time, have so far failed to effectively control.For example: in a single 1986 domestic 200MW units in the electrical system fault in load rejection after shutdown, because electric barring do not cast, manual jigger d

40、evice also failed, forced to use half an hour wheel degrees.3h after the vote on electric barring, swaying of main shaft was gradually restored to the original value.The unit during the hot starting, the deaerator steam balance pipe steam to a shaft seal steam delivery, then vacuum 200mm Hg, at the

41、same time with the main electric valve bypass rotation-impulsing, throttling expansion, main steam temperature is further reduced. into the seal of low temperature steam and the steam into the cylinder, the cylinder is a sudden drop in temperature, temperature difference between upper and lower cyli

42、nder increases, causing the cylinder deformation of arch, the seal sleeve shrinkage deformation, leading to seal and shaft friction local overheat bending.Disassembling inspection shaft high pressure steam seal bend 0.5mm, straight shaft processing recovery after operation. in a single domestic 200M

43、W units, minor repairs after starting running soon.Because the generator water protection maloperation off, followed by successive start, because of large vibration and shutdown.After disassembling, high pressure steam seal high pressure rotor bend 0.30mm, checked the engine high pressure cylinder t

44、o the B column offset, offset 1mm front, rear offset 0.76mm, reason is the front positioning pin hole misplacement of 1.5mm, is not installed during the installation positioning pin, leading to not run in uniform stress so that the cylinder offset.Overhaul on both sides of the measurement radial cle

45、arances also found cylinder offset.Accident shortly before a stop, a rotor in the 90r / min suddenly stop speed, this did not identify reason analysis.So in the water protection maloperation shutdown process, high pressure steam seal and shaft in high speed friction, leading to large shaft bending,

46、after direct axis processing, and eliminate the sliding pin system defect recovery after operation. in a single domestic 220MW units, shutdown after the hot start, due to shaft seal for valve leakage, in cylinder temperature 406 C305 C under the condition of boiler steam leakage into the cylinder, t

47、he cylinder, the rotor being uneven cooling, large shaft temporary deformation.But when starting, and because of shaking table drive rod wear, has been directed at 0.05mm constant, when the first time in the 500r / min No. 2 bearing vibration exceeds 0.10mm, the biggest to the 0.13MM is called gate

48、stop after stop, not seriously find the reasons, mistakenly believe that Akira 0.05mm has reached the original value, and the lack of barring gear 4H on two start, to the 1368r / min No. 3 bearing vibration of 0.13MM, a gate stop.Disassembling inspection regulation of class 0.39mm high pressure roto

49、r bend, the straight shaft processing recovery after operation. in a single 200MW unit cold start, high pressure inner cylinder wall temperature measuring points of failure, when the rotational speed is up to 1000r / min, vibration increases suddenly, but field operation personnel to the control roo

50、m to report, delayed time down.Stop opening cylinder inspection found high pressure inner cylinder drain pipe fracture, high pressure rotor shaft bending analysis that exceed the standard, high pressure cylinder starting of large temperature difference in the effects of deformation, leading to steam

51、 seal and shaft friction cause permanent bending, the straight shaft processing recovery after operation.The accident case especially in recent years the accident of main shaft bending of main shaft bending of that, to prevent the anti accident measures have yet to be carried out seriously falls.The

52、 occurrence of large shaft bending, will cause the machine long time of shutdown, the disassembly of the straight shaft, using pressurized straight shaft, the rotor gradually heated to above 650 degrees C can be pressurized, because the heating process is easy to fail to rework, often prolonged peri

53、od, resulting in a passive and trouble to power plant.Therefore, in order to prevent the accident of main shaft bending, should be combined with actual equipment situation, comprehensive carry out seriously or reference implementation of Ministry of water and electricity fire word 1985 87 and 1985 r

54、adical fire word no. 69, issued on the prevention of main shaft bending of 200 MW unit technical measures, all measures to fulfil requirements, field operation procedures and operation management, maintenance management, equipment management, and to emphasize the following points: in accordance with

55、 the prevention of main shaft bending of the requirements of technical measures, organize main duty personnel and factory, workshop in charge of running the leading and professional personnel to master the technical data and exact data, such as large shaft swaying of scales measuring installation po

56、sition, main shaft swaying of the original value, unit shafting bearings and start normal operation the original vibration value, flow path radial, axial clearance value and so on, so that the commander and the operator to know the score. according to the unit equipment, implementation of the techni

57、cal measures to prevent the cylinder inlet .: units must be examined before the start of swaying of main shaft does not exceed the original value 0.02mm; the high pressure outer cylinder and the intermediate pressure cylinder on the cylinder temperature difference of not more than 50 DEG C; the high

58、 pressure inner cylinder on the cylinder temperature difference of not more than 35 DEG C; the main steam, reheat steam temperature above at least cylinder metal 50 C , not less than 50 degrees ; do not meet the above conditions prohibit unit. units should be conducted before turning fully turning ,

59、 if turning short interruption, they should be the interrupt time 10 times plus 4H continuous barring may rush to turn. starting in medium speed, bearing vibration than 0.03mm should call gate stop, critical vibration more than 0.10mm should call gate stop, no break line speed boot.Downtime should s

60、till be continuous barring , we can start again. before the start of steam seal steam temperature shall be higher than the cylinder metal temperature, and should be in the steam delivery before fully hydrophobic, prevent water into steam seal caused by quenching. restart if bearing vibration, change of steam parameter than rules or machine with abnormal sound of friction sparks, shaft seal, should according to the regulations to stop immediate