《锅炉原理》课件ppt08 省煤器和空气预热器econmizer and

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1、8.1Anoverviewofbackpassheatingsurfaces第一节尾部受热面概述8.2Economizers第二节省煤器8.3Airheaters第三节空气预热器8.4Corrosion,plugginganderosionofbackheatingsurfaces第四节尾部受热面的磨损、积灰和腐蚀Chapter8EconomizersandAirHeaters第八章省煤器和空气预热器Economizersandairheatersperformakeyfunctioninprovidinghighoverallboilerthermalefficiencybyr

2、ecoveringthelowlevel(lowtemperature)energyfromthefluegasbeforeitisexhaustedtotheatmosphere.省煤器和空气预热器在现代高效率锅炉系统中扮演重要的作用。Economizersandairheaterslocateatthebackpassinboiler,socalledbackpassheatingsurfacesorlowtemperatureheatingsurfaces.省煤器和空气预热器布置在锅炉系统的尾部，被称为尾部受热面或低温受热面。Inlettemperature<600ºC,o

3、utlettemperature140~170ºC8.1Anoverviewofbackheatingsurfaces§8-1尾部受热面概述1.Functionofbackheatingsurface尾部受热面作用Foreach40F(22C)thatthefluegasiscooledbyaneconomizerorairheaterinaconventionalboiler,theoverallboilerefficiencyincreasesbyapproximately1%.Economizersrecovertheenergybyheatingtheboilerfeed

4、water;Airheatersheatthecombustionair.Airheatingalsoenhancesthecombustionofmanyfuelsandiscriticalforpulverizedcoalfiringtodrythefuelandensurestableignition.8.1Anoverviewofbackheatingsurfaces§8-1尾部受热面概述8.1Anoverviewofbackheatingsurfaces§8-1尾部受热面概述2.Arrangementofbackheatingsurface尾部受热面的布置Fig.2Ec

5、onomizerandairheaterlocationsinatipicalcoal-firedboiler燃煤锅炉典型的省煤器和空气预热器布置烟气每降低1ºC，空气大约升温1.4ºC空气预热器出口温差Δt≥30~40ºC。2.Arrangementofbackheatingsurface尾部受热面的布置图9-2Arrangementofbackheatingsurface尾部受热面的布置8.1Anoverviewofbackheatingsurfaces§8-1尾部受热面概述Single-stageDouble-stage2.Arrangementofbackheatings

6、urface尾部受热面的布置图9-2Arrangementofbackheatingsurface尾部受热面的布置8.1Anoverviewofbackheatingsurfaces§8-1尾部受热面概述8.1Anoverviewofbackheatingsurfaces§8-1尾部受热面概述2.Arrangementofbackheatingsurface尾部受热面的布置图9-2Arrangementofbackheatingsurface尾部受热面的布置双级布置单级布置Question:为什么有不同的布置方式，适用条件是什么？8.1Anoverviewofbackheatin

7、gsurfaces§8-1尾部受热面概述Question:为什么有不同的布置方式，适用条件是什么？对空气预热器对省煤器保证热端温差≥30~40℃保证省煤器入口温差要获得更高的热空气温度，需采用双级布置对于超高压及以上锅炉，除布置低温对流过热器外，还布置再热器，尾部受热面通常采用单级布置。Economizersarefeed-waterheatersinwhichtheheatfromwastegasesisrecoveredtoraisethetemperatureoffeed-