单元机组给水控制系统设计

I摘要随着我国电力市场的实际情况和国民经济发展的需要，电站项目向着高参数、大容量的方向发展已成为大势所趋，近年来超临界发电机组在国内得到迅速发展和应用。超临界锅炉将是国家未来的发展方向，给水系统是其中的重要环节。超临界直流炉的给水控制技术是目前国内热控领域一个重要的研究课题。本论文介绍了超临界机组的概况，分析了超临界锅炉的静、动态特性及控制特点与超临界锅炉给水系统的工艺过程，比较分析了亚临界汽包锅炉与超临界直流锅炉给水系统控制的异同，研究了超临界锅炉给水控制策略。同时针对目前国内普遍使用的600MW超临界直流锅炉的给水控制系统，进行了设计。设计内容主要包括锅炉干/湿态下给水流量控制的切换、PID模块的手/自动的无扰切换、储水箱水位控制等部分，并对设计SAMA图逐一进行说明。关键词：超临界直流炉；给水控制系统；燃水比；中间点温度；中间点焓IITHEDESIGNINGONPLANTUNITFEEDWATERCONTROLSYSTEMAbstractItbecomesatrendthatthepowerstationprojectsgoforwardtohighparameterandlargecapacityinconsiderationofchina’sactualsituationandthedemandofthenationaleconomicdevelopment.Inthepastyearsthesuper-criticalunitwereappliedanddevelopedquickly.Thesupercriticalboilerwillbethefuturenationaitendency,andthewatersupplysystemisanimportantlink.Thefeedwatercontrolofsupercriticaloncethroughboilerisanimportantstudysubjectinthermalfieldatpresent.Thispaperintroducesthegeneralsituationofsupercriticalunit,analysesthestaticordynamiccharacteristicsandthecontrolfeatureofthesupercriticalboiler.Thetechnologicalprocessofsupercriticalboilerfeedwatersystemisanalyzedtoo,Comparativeanalysisthesimilaritiesanddifferencesbetweenthesubcriticalandsupercriticalonce-throughboilersteamdrumboilerfeedwatersystemcontrol,studiesthestrategyofthesupercriticalboilerfeedwatercontrol.Atthesametime,designsthe600MWsupercriticalonce-throughboilerfeedwatercontrolsysteminviewofthepresentdomesticuniversal.DesigncontentmainlyincludesBoilerfeedwaterflowcontrolunderthewet/drystateswitch,runningstateoftheswitchofhand/autoundisturbedswitchingofPIDmodule,storagetankwaterlevelcontrol,illustratesthedesignSAMAgraphonebyone.KeyWords：Supercriticalonce-throughboiler;Feedwatercontrolsystem;Coaltowaterratio;Intermediatepoint’senthalpy;Intermediatepoint’stemperature目录摘要......................................................................IAbstract....................................................................II1绪论....................................................................11.1论文研究的背景和意义...................................................11.2国内外研究动态.........................................................11.3论文的主要工作.........................................................21.4本章小结...............................................................32超临界直流锅炉概述........................................................42.1超临界机组简介.........................................................42.1.1超临界机组定义.......................................................42.1.2超临界机组在国外的应用...............................................42.1.3超临界机组在我国的应用...............................................52.2超临界直流锅炉.........................................................62.2.1直流炉的工作原理.....................................................62.2.2超临界直流炉的静态特性...............................................72.2.3超临界直流炉的动态特性...............................................82.3超临界机组的控制特点...................................................92.3.1汽包锅炉的控制特点...................................................92.3.2超临界锅炉的控制特点................................................102.3.3超临界直流炉和汽包炉控制系统比较....................................102.3.4超临界锅炉的控制任务................................................112.4超临界锅炉的给水控制系统..............................................122.4.1锅炉给水控制系统的主要任务..........................................122.4.2锅炉给水系统的工艺流程...............................................122.5几种常见的超临界锅炉给水控制方案简介..................................132.5.1超临界直流锅炉燃水比控制............................................132.5.2中间点温度校正的给水控制系统简介....................................152.5.3中间点焓值校正的给水控制系统........................................162.6本章小结..............................................................173600MW超临界机组给水系统控制设计.........................................183.1600MW超临界机组的给水系统设计背景.....................................183.1.1给水控制系统的指令..................................................183.1.2给水系统控制方案....................................................193.2600MW超临界机组的给水系统控制方案.....................................213.2.1给水流量定值形成说明................................................303.2.2电泵给水流量调节说明................................................303.2.3给水旁路阀水位辅助调节系统调节原理..................................303.2.4汽泵给水流量调节说明................................................303.3600MW超临界机组的储水箱水位调节系统控制方案...........................313.3.1储水箱水位补偿说明..................................................413.3.2储水箱水位控制说明..................................................413.4本章小结..............................................................41结论.....................................................................42参考文献...................................................................43致谢.....................................................................4411绪论1.1论文研究的背景和意义电力工业在我国国民经济中有着非常重要的作用。我国电力工业在新的起点上实现了又好又快发展，发电量和电网规模已居世界第一位。转变发展方式进展明显，电源结构逐步优化，水电装机2.3亿千瓦，年发电量6900亿千瓦时，风电并网运行规模超4500万千瓦，均居世界第一。技术装备水平显著提高，在大型空冷机组、循环流化床机组应用等方面取得国际领先地位[1]。超临界锅炉具有发电效率高、负荷适应性强等特点，是中国未来大型锅炉的发展趋势，深入研究并掌握其动态特性是十分重要的。直流锅炉是指靠给水泵压力，使给水顺序通过省煤器、蒸发受热面、过热器并全部变为过热蒸气的锅炉。由于给水在进入