600MW机组凝结水含氧量超标的危害和预防.pptVIP

600MW机组凝结水含氧量超标的危害和预防600MWunitscondensateoxygencontentofthehazardsofexcessiveandprevention

◆凝结水溶解氧是化学监督的主要指标之一,特别是600M机组对凝结水溶解氧含量有更高的要求.因为溶解氧大幅度超标或长期不合格,会加速凝结水管道及设备的腐蚀,并使凝结水中含有氧化铁离子,引起电化腐蚀,使传热恶化,直至发生锅炉爆管,严重威胁机组安全、经济运行。Condensateofdissolvedoxygenisoneofthemainindicatorsofthechemicalsupervision,600MWunitscondensatedissolvedoxygencontenthigherdissolvedoxygen,becausealotofexcessiveorlong-termfailure,Itwillacceleratethecondenspipelineandequipmentcorrosion,andmakecondensatcontainsironoxideions,causinggalvaniccorrosion,Heattransferdeterioration,untiltheoccurrenceofboilertube,andcrewsandeconomicoperationofunits.1

?1.vacuumsystemisnottight,alotofairtoenterthecondenser;?2.higherlevelsofdissolvedoxygenreplenishwaterorrecycledwaterenterthecondenser◆凝结水溶解氧存在的原因:?1.真空系统不严密，进入凝结器的漏量大；?2.有溶解氧含量较高的补水或回收水大量进入凝结器；◆Condensateofdissolvedoxygenreasonsfortheexistence:

□针对上述原因，从以下方面进行防范和处理:?Fortheabovereasons,fromthefollowingaspectspreventandtreatment:

◆1.真空系统的查漏?运行中真空系统的查漏以氦介质检漏为主。方法是在运行真空泵出口布置氦介质检漏装置,利用专用的喷枪在所有负压系统的阀门、法兰、管道焊缝、排大气口等处喷氦气,然后观察1-2分钟,如果检测点有泄露,检漏装置就会发出报警,泄漏量越大,报警数值就越大,即使很微量的泄露,也能检测出来。并且这种方法灵活,不受时间限制,消除漏点后随时可以检测溶解氧的变化。缺点是工作量大,耗时长。

◆1.vacuumsystemleak?runningvacuumsystemleakismainlyheliummediumLeak.runningvacuumpumpoutletlayouttheheliummediumleakdetectiondevices,withadedicatedgunsprayheliumtoallnegativepressuresystemvalves,flanges,pipeweldsandexclusiveatmospheremouthetc,thenobservedfor1-2minutes,ifitdetectssomeleakage,andtheleakdetectiondevicewalarm,thegreatertheamountofleakage,thegreaterthealarmvalue,evenaverysmallamountofleakagecanbedetected.themethodisflexible,withouttimelimit,aftereliminatetheleak,atanytimethec