南师大锅炉原理课件7-4 蒸汽温度调节

2025/6/2211.EffectsofoperatingvariableonST汽温影响因素(pp.19-13)Boilerload

锅炉负荷:负荷增加，汽温上升Excessair

过量空气系数：α增加，对流传热加强，Ts上升Feedwatertemperature

给水温度降低，燃料量增加，燃烧常务的容积增加，出口烟温升高，汽温上升HeatingsurfacesCleanlinessof受热面的污染情况炉膛受热面结渣或积灰，炉内辐射传热量减少，过热器区域烟气温度升高，汽温升高过热器本身结渣或积灰，导致汽温下降UseofSaturatedsteam

饱和蒸汽用汽量BurnerOperation

燃烧器的运行方式,火焰中心提高,Ts上升Fueltypeandcomposition

燃料种类和成分,煤粉变粗，水份增大或灰分增加，过热汽温提高。7.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/2227.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节steamtemperaturecharacteristics

汽温特性过热器或再热器出口汽温与锅炉负荷之间的关系(Fig.19-12)Convectionsuperheater对流式过热器Atmaximumload,or100%steamoutput,thegasweightishighest;heattransferisalsohigh.Thehigherheatabsorptionresultsinhighersteamtemperatureleavingthesuperheaterandahigherboileroutput. 随着负荷的增加，汽温增加。Radiantsuperheater辐射式过热器Thesteamtemperatureleavingtheradiantsuperheaterislowestathigherloadsfortworeasons.RadiantabsorptiondoesnotincreaseasrapidlyasboileroutputAthigherloadsthereismoresteamtocooltheeffectsoftheradiantabsorption. 随着负荷的增加，汽温降低。

2025/6/2237.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/2247.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2.SteamtemperatureAdjustment蒸汽温度调节Permitsatoleranceof-10~+5ºCinaspecificsteamoutlettemperatureduringoperation 运行中汽温允许波动值范围：-10~+5ºCBasicrequirementsforadjustivedevice对调节设备的要求Simplystructure,reliablyoperation 设备结构简单，运行可靠Sensitive,littledeviationofsteamtemperature,easilyautomatic调节灵敏，汽温偏差小，易实现自动化Havenobadeffectsonboilerandsystemefficiency 不影响锅炉或热力系统的效率keepthestablesteamtemperatureattherangeofload. 在一定的负荷范围内(60~100%)保持额定的蒸汽温度2025/6/2257.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2.SteamtemperatureAdjustment蒸汽温度调节Adjustivemethods调节方法STadjustmentonsteamside蒸汽侧调节汽温Surfaceattemperator表面式减温器Steam-steamexchanger汽-汽交换器Sprayattemperator喷水减温STadjustmentonfluegasside烟气侧调节汽温Gasproportioningdamper烟气挡板Gasrecirculation烟气再循环Swingburner摆动式燃烧器多种调温方式结合使用：摆动式燃烧器调节烟气挡板喷水减温2025/6/2267.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节1)Surfaceattemperator表面式减温器Surfaceattemperatorincludestheshelltypeandthedrumtype,thesteamisisolatedfromthecoolingmediumbytheheatexchangersurface.

表面式减温器是一种U型管、套管、螺旋管等类型换热器，冷却水在管内纵向流动，蒸汽在管外横向冲刷管子，通过改变减温水量调节汽温Surfacetypeattemperatorsareoccasionallyusedonsomeindustrialboiler,theboilerfeedwaterisused,thequantityofattemperationwateris30~60%totalfeedwater. 一般用于中小容量锅炉，采用锅炉给水来冷却蒸汽，减温水量占总给水量的30~60%Thecoolingwaterdoesnotcontactwithsteam,sonoextrarequirementforwaterquality.

冷却水与蒸汽不接触，对冷却水的品质无特殊要求AdjustmentInertia,accommodativeamplitude调节惯性大，调节幅度小2025/6/2277.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/2287.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2)Spraytypeattemperator喷水减温将减温水通过雾化喷嘴雾化后直接喷入过热蒸汽中，吸热蒸发，达到调节汽温的目的。结构简单，调节幅度大，惯性小，调节灵敏，有利于自动调节.直接与蒸汽接触，对水质要求高.喷水减温器的结构Swirling旋涡式(图7-20)Multi-orificejetnozzle多孔喷管式(图7-21)Venturi文丘里式2025/6/2297.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/2210锅炉给水作减温水的连接系统7.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/22117.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/22127.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2)Spraytypeattemperator喷水减温Arrangementprinciples喷水减温器的布置原则保证调节灵敏保护过热器不超温Arrangementmode喷水减温器的布置方式(图7-23)Locateatthesystemoutlet减温器布置于系统出口，调节灵敏，但金属温度高，安全系数小Locateatthesysteminlet布置于入口端，过热器金属温度较低，但调节惰性大，时滞长Multi-stage,locateattheinletofhigh-TSH多级减温，布置在屏式、高温对流过热器的入口2025/6/22137.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/22147.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节3)Steam-steamexchanger汽-汽交换器用过热蒸汽来加热再热蒸汽，主要用于调节再热蒸汽温度过热蒸汽来自辐射型过热器，其汽温随锅炉负荷下降而上升再热器为对流型，其其汽温随锅炉负荷下降而下降按布置位置可以分为两类：External外置式：布置于烟道外Internal内置式：布置于烟道内按结构可分为：管式(图8-26)筒式结构复杂，钢耗大，运行不稳。2025/6/22157.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/22167.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/22177.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节4)Fluegasrecirculation烟气再循环(图7-30)将省煤器后的烟气由再循环风机抽出再送入炉膛。炉膛上部：降低炉膛出口烟气温度，防止高温过热器高温腐蚀和结渣炉膛下部：降低水冷壁的温度，提高对流受热面的吸热量。烟气再循环的优点调节幅度大，灵敏度高均匀炉膛热负荷，降低水冷壁温度减少再热器受热面积，节约钢材烟气再循环的缺点增加肋再循环风机，消耗一定的电能烟气温度高，含灰多，磨损严重，可靠性差炉膛温度降低会影响燃烧的稳定性锅炉排烟温度升高，热损失增加。2025/6/22187.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/22197.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节5)Fluegasbaffle烟气挡板(图7-27)通过改变锅炉内辐射受热面和对流受热面的吸热量分配比例的方法或改变流经过热器的烟气量的方法来实现汽温调节。Bypassduct旁通烟道平行烟道：再热器与省煤器并联、再热器与过热器并联。6)Swingtypeburner摆动式燃烧器调节摆动式燃烧器喷嘴的上下倾角，可以改变炉内火焰的中心位置，喷嘴向上倾斜时，火焰中心上移，炉膛出口烟温升高，对流受热面吸热量增加。四角布置的直流燃烧器采用摆动燃烧器；旋流燃烧器采用分层布置，分层燃烧方式。灵敏度高，调节方便在亚临界和超临界锅炉上应用较多2025/6/22207.4Steamtemperatureadjustmentandcontrol

§7-4蒸汽温度调节2025/6/22217.4Steamtemperatureadjustmentandcont