2025/6/2218.2Economizers

§8-2省煤器Economizersarefeed-waterheatersinwhichtheheatfromwastegasesisrecoveredtoraisethetemperatureoffeed-watersuppliedtotheboiler.Theyofferthefollowingadvantages:FueleconomyLongerlifeoftheboilerIncreaseinsteamingcapacityFinnedTubeEconomizers鰭片管省煤器C.I.GilledTubeEconomizers肋片管省煤器PlainTubeCoilEconomizers光片管省煤器2025/6/2228.2Economizers

§8-2省煤器1.FunctionofEconomizer省煤器的作用Thetermeconomizercomesfromearlyuseofheatexchangerstoreduceoperatingcostsoreconomizeonfuelbyrecoveringextraenergyfromthefluegas. 利用換熱器可以節省燃料，降低運行費用，故稱為省煤器Economizeralsoreducethepotentialofthermalshockandstrongwatertemperaturefluctuationsasthefeedwaterentersthedrumorwaterwalls.當給水進入鍋筒和水冷壁時，降低熱沖擊的潛力和強烈的水溫波動。Savingfuel節省燃料Improvingtheworkingconditionofstreamdrum改善汽包工作條件Reducethecapitalcostsofboiler降低鍋爐造價2025/6/2238.2Economizers

§8-2省煤器西交大省煤器動畫2025/6/2248.2Economizers

§8-2省煤器2.Economizertypes省煤器的種類Classifiedbymaterials按材料分類Castiron鑄鐵:只用于工作壓力低于4MPa的鍋爐中，強度低不能承受高壓，耐磨耐腐蝕性好，通常用在小容量鍋爐上。Steeltube鋼管：強度高，能承受沖擊，工作可靠，傳熱性能好，重量輕，體積小，價格低，耐磨耐腐蝕性較差.Classifiedbyoutletwatertemperature按給水溫Steamingtype沸騰式:汽化水量占總給水量10~15%,中壓鍋爐由于水的汽化潛熱較大，為減少蒸發受熱面的吸熱量，防止爐內溫度過低影響燃燒的穩定性，常采用。Non-steamingtype

非沸騰式:一般低于飽和點20~25oC，隨著壓力的提高，水的氣化潛熱減少，液相加熱到飽和溫度所需預熱熱增大，將水的部分加熱過程轉移到爐內進行，以防止爐膛出口煙溫過高。2025/6/2258.2Economizers

§8-2省煤器3.Economizersurfacetypes省煤器的表面型式Baretube光管省煤器ThemostcommonandreliableeconomizerdesignIn-line(順列),crossflow(橫向流動)Staggered(錯列)，crossflows2s1SidespacingBackspacingFluegass2s1S1/d=2~2.5S2/d=1~1.5S1/d=2~2.5S2/d=22025/6/2268.2Economizers

§8-2省煤器2025/6/2278.2Economizers

§8-2省煤器Extendedsurfaces擴展表面（pp.194圖8-3）Toreducecapitalcosts,mostboilermanufacturershavebuilteconomizerswithvarietyoffin(鰭片)typestoenhancethecontrollinggas-sideheattransferrate.Finsareinexpensivepartswhichcanreducetheoverallsizeandcostofaneconomizer.Surfacecleanabilityisakeyconcern.Studfins(銷釘鰭片):performedpoorlyincoal-firedboilersHelically-finned(螺旋鰭片):

pluggingwithflyashcanalsobeaproblem.Longitudinalfins(縱向鰭片):

successfullyappliedtosomecoal-,oil-andgas-firedunitsRectangularfin(矩形鰭片):arrangedperpendiculartothetubeaxisonin-linetubes.2025/6/2288.2Economizers

§8-2省煤器2025/6/2298.2Economizers

§8-2省煤器2025/6/22108.2Economizers

§8-2省煤器體積比光管小25~30%2025/6/22118.2Economizers

§8-2省煤器2025/6/22128.2Economizers

§8-2省煤器4.ArrangementofEconomizer省煤器的布置通常布置在對流煙道中，一般將管圈放置成水平以利于排水總是保持水由下向上流動，以便于排出其中的空氣，避免引起局部的氧氣腐蝕。煙氣從上向下流動，既有利于吹灰，又保持煙氣相對于水的逆向流動，增大傳熱溫差。Φ42~51蛇形管緊密布置，管組高度≤1m布置較稀時，管組高度≤1.5m管組之間≥600~800mm2025/6/22138.2Economizers

§8-2省煤器TypeofSteeltubeEconomizer鋼管式省煤器的結構直徑為42~51mm蛇行管與進出口聯箱header組成(圖8-1).Staggered錯列布置：橫向管節距s1/d=2~2.5;縱向管節距s2/d=1~1.5In-line順列布置：橫向管節距s1/d=2~2.5;縱向管節距s2/d=2.0。省煤器一般臥式布置于煙道中，有利于傳熱，也便于停爐排除積水。2025/6/22148.2Economizers

§8-2省煤器ArrangementofEconomizer省煤器的布置一般采用錯列布置Staggered在尾部煙道中，傳熱效果好，結構緊湊，但磨損嚴重，吹灰困難。按蛇行管放置方向不同分為(圖8-4):Longitudinal縱向布置：蛇行管放置方向于鍋爐的前后墻垂直perpendicularTransverse

橫向布置：蛇行管

放置方向于鍋爐的前后墻平行parallel.2025/6/22158.2Economizers

§8-2省煤器5.Economizersupportsystem省煤器的支吊Economizersarelocatedwithintubewallenclosuresorwithincasingwallsdependingongastemperatures.Casing(外套)enclosuresareusedatorbelow454oCandinexpensivecarbonsteelcanbeused.Endsupports支承結構(圖8-5)：中小型鍋爐省煤器Stringersupports懸吊結構(圖8-6)

:大型鍋爐省煤器Supportbars支撐梁Vibrationdampers阻振裝置2025/6/22168.2Economizers

§8-2省煤器Endsupports支承結構(圖8-5)

：中小型鍋爐省煤器2025/6/22178.2Economizers

§8-2省煤器2025/6/22188.2Economizers

§8-2省煤器Stringersupports懸吊結構(圖8-6)

:大型鍋爐省煤器2025/6/22198.2Economizers

§8-2省煤器Stringersupports懸吊結構(圖9-7)

:大型鍋爐省煤器2025/6/22208.2Economizers

§8-2省煤器2025/6/22218.2Economizers

§8-2省煤器6.Connectionoftubeswithdrum省煤器引出管與汽包的連接（圖8-7）溫度差異保護汽包2025/6/22228.2Economizers

§8-2省煤器7.Economizerperformance省煤器設計中應考慮的問題Waterflowvelocityinsnaketubes蛇行管內水流速度Flowvelocityhaveeffectsonheattransfer,resistance,andcorrosion影響傳熱、阻力損失，管內金屬腐蝕Non-steamingeconomizer:v>0.5m/s防止氧腐蝕steamingeconomizer:v≥1m/s防止汽水分層Fluegasvelocity管外煙氣流速Shouldconsidertheeffectsofheattransfer,erosion,andashdeposit綜合考慮傳熱、磨損和積灰三個因素的影響wy=8~11m/s省煤器的結構設計管徑：Φ42-51管子數量：給水量、比體積、內徑和平均流速管子的橫向和縱向節距：積灰指數（見表8-1，pp.198）2025/6/22238.2Economizers

§8-2省煤器8.Economizersafestartup省煤器啟動保護Startupworkingcondition啟動工作條件Discontinuousfeedwater間斷給水Badwaterfluidity水流動性差Continuouslyheatedbyhightemperaturefluegas高溫煙氣不斷加熱