冷卻塔全接觸

262 McQuay中國 ByNickChan 陳萬里 262 ByNickChan 陳萬里 Coolingtower冷卻塔 Agenda TrainingAgenda CoolingTowers Introduction簡介Typesofcoolingtowers類型Assessmentofcoolingtowers評估Energyefficiencyopportunities節(jié)能方案 Introduction冷卻塔簡介 MainFeaturesofCoolingTowers整體結(jié)構(gòu) Introduction Frameandcasing supportexteriorenclosures支架和塔體 外部支撐Fill facilitateheattransferbymaximizingwater aircontact填料 為水和空氣提供盡可能大的換熱面積 Componentsofacoolingtower冷卻塔組成部分 Introduction Splashfill dropletsofwatersplashover preventfouling噴淋式 將水呈水霧狀噴出 這樣的方式可以避免塔內(nèi)結(jié)垢 Filmfill layersofwaterfallover moreefficient butmoreexpensive水膜式 水呈膜狀順填料表面流下 效率較高但是成本高昂 Coldwaterbasin receiveswateratbottomoftower冷卻水槽 位于冷卻塔底部 接收冷卻水 Introduction 噴淋式水膜式 Introduction Drifteliminators收水器 capturedropletsinairstream回收空氣流帶走的水滴Airinlet進(jìn)風(fēng)口 entrypointofair冷卻塔空氣入口Louvers冷卻塔百葉窗 equalizeairflowintothefillandretainwaterwithintower平均進(jìn)氣氣流 保留塔內(nèi)水分 Componentsofacoolingtower冷卻塔組件 Introduction Nozzles淋水裝置 spraywatertowetthefill將冷卻水噴出Fans風(fēng)機(jī) deliverairflowinthetower向冷卻塔內(nèi)送風(fēng)Propellerfansusedininduceddrafttowers軸流風(fēng)扇用于誘導(dǎo)通風(fēng)冷卻塔Propeller centrifugalfansusedinforceddrafttowers軸流 離心風(fēng)扇用于強(qiáng)制通風(fēng)冷卻塔 TrainingAgenda CoolingTowers Introduction簡介Typesofcoolingtowers類型Assessmentofcoolingtowers評估Energyefficiencyopportunities節(jié)能方案 TypesofCoolingTowers冷卻塔種類 Hotairmovesthroughtower密度較小的熱空氣自冷卻塔頂部流出Freshcoolairisdrawnintothetowerfrombottom密度較大的冷空氣自塔底部進(jìn)入冷卻塔填補(bǔ) NaturalDraftCoolingTowers自然通風(fēng)冷卻塔 TypesofCoolingTowers冷卻塔種類 Nofanrequired不需風(fēng)機(jī)Concretetower 200m混凝土塔 200mUsedforlargeheatduties用于大熱量的冷卻 NaturalDraftCoolingTowers自然冷卻塔 TypesofCoolingTowers冷卻塔種類 NaturalDraftCoolingTowers自然冷卻塔 橫流 對流 TypesofCoolingTowers冷卻塔類型 兩種冷卻塔 橫流 對流 TypesofCoolingTowers冷卻塔種類 Largefanstoforceairthroughcirculatedwater大功率風(fēng)機(jī)強(qiáng)制空氣與循環(huán)水的換熱Waterfallsoverfillsurfaces maximumheattransfer填料表面的水膜可以最大限度地與空氣進(jìn)行換熱 MechanicalDraftCoolingTowers機(jī)械通風(fēng)冷卻塔 TypesofCoolingTowers冷卻塔種類 Coolingratesdependonmanyparameters冷卻效率的決定因素有很多Largerangeofcapacities多種冷卻能力備選Canbegrouped e g 8 celltower可以多冷卻塔同時(shí)工作 例如8塔聯(lián)控 TypesofCoolingTowers冷卻塔種類 Threetypes機(jī)械通風(fēng)冷卻塔分為三類 Forceddraft強(qiáng)制通風(fēng)冷卻塔Induceddraftcrossflow誘導(dǎo)通風(fēng)橫流冷卻塔Induceddraftcounterflow誘導(dǎo)通風(fēng)逆流冷卻塔 MechanicalDraftCoolingTowers TypesofCoolingTowers Airblownthroughtowerbycentrifugalfanatairinlet空氣由離心風(fēng)扇吹入通風(fēng)口Advantages suitedforhighairresistance fansarerelativelyquiet優(yōu)勢 適用于氣流阻力較大的塔體 離心風(fēng)扇噪聲相對較小 ForcedDraftCoolingTowers Disadvantages recirculationduetohighair entryandlowair exitvelocities劣勢 由于進(jìn)氣流速高于排氣流速 會(huì)出現(xiàn)回流 19 CoolingTowerBasics ForcedDraft強(qiáng)制通風(fēng)CounterflowTower逆流冷卻塔 Waterissprayedontothefillandfallstothetowerbasin 冷卻水被噴淋在填料上 向下流入冷卻水槽 Airisblownupthroughthefillandevaporatessomeofthewaterandreducesthewatertemperature 空氣從底部強(qiáng)制吹入 在填料內(nèi)與水接觸蒸發(fā)部分冷卻水 從而降低水溫 TypesofCoolingTowers Twotypes誘導(dǎo)通風(fēng)冷卻塔分兩類 Crossflow橫流式誘導(dǎo)通風(fēng)冷卻塔Counterflow逆流式誘導(dǎo)通風(fēng)冷卻塔 InducedDraftCoolingTowers誘導(dǎo)通風(fēng)冷卻塔 TypesofCoolingTowers Advantage lessrecirculationthanforceddrafttowers lowermotorrunningcost優(yōu)勢 回流程度低于強(qiáng)制通風(fēng)冷卻塔 風(fēng)機(jī)運(yùn)行費(fèi)用小于強(qiáng)制通風(fēng)冷卻塔 Disadvantage fansandmotordrivemechanismrequireweather proofing劣勢 風(fēng)扇與電機(jī)的機(jī)械傳動(dòng)需要防水設(shè)計(jì) TypesofCoolingTowers Hotwaterentersatthetop熱水從頂部進(jìn)入冷卻塔Airentersatbottomandexitsattop空氣通過風(fēng)扇強(qiáng)制誘導(dǎo) 從底部進(jìn)入冷卻塔Usesinduceddraftfans使用強(qiáng)制誘導(dǎo)風(fēng)扇 InducedDraftCounterFlowCT 23 CoolingTowerBasics InducedDraft誘導(dǎo)通風(fēng)CounterflowTower逆流式 WaterissprayedontotheFillandfallstothetowerBasin冷卻水從頂部噴入 流經(jīng)填料層進(jìn)入冷卻水槽 AirisdrawnthroughtheFillandevaporatessomeOfthewaterandreducesTheremainingwatertemperature 空氣由誘導(dǎo)風(fēng)機(jī)引入冷卻塔從底部 在填料內(nèi)與水接觸蒸發(fā)部分冷卻水 從而降低水溫 CoolingTowerBasics Duetotheirpressurizedspraywaterdistributionsystem因?yàn)榇祟惱鋮s塔內(nèi)的加壓配水噴淋裝置 Advantages優(yōu)勢 Increasedtowerheightaccommodateslongerrangesandcloserapproaches通過增加塔的高度來獲得更長的換熱流程與更小的冷幅Moreefficientuseofairduetofinerdropletsizefrompressuresprays由于加壓噴淋裝置可以噴出更小的水滴 因此換熱效率較高 Induceddraft counterflow逆流式誘導(dǎo)通風(fēng)冷卻塔 CoolingTowerBasics Disadvantages劣勢 Increasedsystempumpingheadrequirements系統(tǒng)水泵壓頭增加Increasedenergyconsumptionandoperatingcosts能量需求增大 運(yùn)行費(fèi)用增加Distributionnozzlesdifficulttoinspectandclean冷卻水噴頭不易維護(hù)和清潔Requiresextradistributorandexternalpipingcosts需要配水系統(tǒng)以及相關(guān)管路 因此初投資增加 TypesofCoolingTowers Waterenterstopandpassesoverfill冷卻水從頂部進(jìn)入 流經(jīng)填料層Airentersononesideoroppositesides空氣從一側(cè)或兩側(cè)進(jìn)入Induceddraftfandrawsairacrossfill誘導(dǎo)風(fēng)機(jī)使空氣橫向流過填料層 InducedDraftCrossFlowCT橫流式誘導(dǎo)通風(fēng)冷卻塔 27 CoolingTowerBasics InducedDraftCrossFlowTower WaterissprayedontotheFillandfallstothetowerBasin FillisdeeperlargerSurfacearea 冷卻水噴淋至填料層 從頂部流至底部的冷卻水槽 AirisdrawnthroughtheFillandevaporatessomeOfthewaterandreducesThewatertemperature Lessairrequired空氣由誘導(dǎo)風(fēng)機(jī)引入冷卻塔側(cè)面 在填料內(nèi)橫向流動(dòng)與水接觸蒸發(fā)部分冷卻水 從而降低水溫 CoolingTowerBasics Duetotheirgravityflowhotwaterdistributionsystem由于此類冷卻塔的水屬于自然流配水系統(tǒng) Advantages優(yōu)勢 Lowpumpinghead低水泵壓頭Lowerfirstcostpumpingsystems較低的水泵初投資Lowerannualenergyconsumptionandoperatingcosts較低的年運(yùn)行能耗和費(fèi)用Acceptslargervariationinwaterflowwithoutadverseeffectonthewaterdistributionpattern流量變化較大時(shí)不會(huì)對配水系統(tǒng)造成不利的影響 Induceddraft crossflow橫流式誘導(dǎo)通風(fēng)冷卻塔 CoolingTowerBasics Disadvantages劣勢 Lowpressureheadonthedistributionpanmayencourageorificecloggingandlesswaterbreakupatspraynozzle低壓頭會(huì)導(dǎo)致噴頭易于堵塞以及冷卻水噴出時(shí)不能很好的分散成細(xì)密水霧Exposuretoairinthehotwaterbasinmayacceleratealgaegrowth熱水水槽直接暴露于空氣中會(huì)導(dǎo)致藻類的滋生Largerfootprint占地面積較大 TrainingAgenda CoolingTowers Introduction簡介Typesofcoolingtowers類型Assessmentofcoolingtowers評估Energyefficiencyopportunities節(jié)能方案 AssessmentofCoolingTowers MeasuredParameters應(yīng)測量的參數(shù) Wetbulbtemperatureofair空氣濕球溫度Drybulbtemperatureofair空氣干球溫度Coolingtowerinletwatertemperature冷卻塔進(jìn)水溫度Coolingtoweroutletwatertemperature冷卻塔出水溫度Electricalreadingsofpumpandfanmotors水泵和電機(jī)運(yùn)行參數(shù)Waterflowrate水流速度Airflowrate空氣流速 PerformanceParameters運(yùn)行參數(shù) Range冷卻水溫差A(yù)pproach冷幅Effectiveness效率Coolingcapacity冷卻塔容量Evaporationloss蒸發(fā)損失Cyclesofconcentration濃縮倍數(shù)Blowdownlosses排污損失Liquid Gasratio液體 氣體比 AssessmentofCoolingTowers 1 Range冷卻水溫差 Differencebetweencoolingwaterinletandoutlettemperature 冷卻水進(jìn)出水溫差 Range C CWinlettemp CWoutlettempHighrange goodperformance大溫差 高性能 AssessmentofCoolingTowers 2 Approach冷幅 Differencebetweencoolingtoweroutletcoldwatertemperatureandambientwetbulbtemperature 冷卻塔出水溫度與入口空氣濕球溫度的差值 Approach C CWoutlettemp WetbulbtempLowapproach goodperformance小冷幅 高性能 AssessmentofCoolingTowers 3 Effectiveness效率 Effectivenessin Range Range Approach 效率 冷卻水溫差 冷卻水溫差 冷幅 Higheffectiveness goodperformance高效率 高性能 AssessmentofCoolingTowers 4 CoolingCapacity冷卻塔容量 HeatrejectedinkCal hrortonsofrefrigeration TR massflowrateofwaterXspecificheatXtemperaturedifference冷卻塔容量單位為 千卡每小時(shí) 或者 冷噸 冷卻塔容量 冷卻水質(zhì)量流量X水的比熱容X溫差Highcoolingcapacity goodperformance大容量 高性能 AssessmentofCoolingTowers 5 EvaporationLoss蒸發(fā)損失 Waterquantity m3 hr evaporatedforcoolingduty蒸發(fā)損失的單位為 m3 hr 表示每小時(shí)因?yàn)槔鋮s而損失的水量 theoretically 1 8m3forevery10 000 000kCalheatrejected理論上蒸發(fā)損失為1 8立方米 1千萬千卡 0 00085x1 8x流量 m3 hr x冷卻水溫差 AssessmentofCoolingTowers AssessmentofCoolingTowers 5 EvaporationLoss蒸發(fā)損失 CoolingTowerIndustry CTI RatesTowersAtARICondenserWater工業(yè)冷卻塔的ARI工況 Waterflowrateacrosscoolingtower 0 054 L s Kw冷卻塔流量 0 054 L s KwCoolingtowercapacity 3500kW冷卻塔容量 3500kW29 4 LeavingFluid出水溫度29 4 35 EnteringFluid進(jìn)水溫度35 Usetheformulafrompreviouspage應(yīng)用前一頁的公式 0 00085x1 8x流量 m3 hr x冷卻水溫差 0 00085x1 8x680 4x 35 29 4 5 82m3 hrA3500kWTowerCanConsume5820LitersPerHourofMakeupWaterDueToEvaporation一個(gè)3500kW冷卻塔的冷卻水蒸發(fā)量為5820升每小時(shí) AssessmentofCoolingTowers 6 Cyclesofconcentration濃縮倍數(shù) Ratioofdissolvedsolidsincirculatingwatertothedissolvedsolidsinmakeupwater循環(huán)水中固態(tài)溶解物含量與補(bǔ)充水中固態(tài)溶解物的含量之比Increasethistoreducewaterloss增加此比例可減小蒸發(fā)損失 7 Blow down排污量 Dependoncyclesofconcentrationandtheevaporationlosses決定于循環(huán)水濃度與蒸發(fā)損失Blow down circulatingwaterremovedamounttomaintaintheamountofdissolvedsolidsandotherimpuritiesatanacceptablelevel EvaporationLoss C O C 1 排污量 為將固態(tài)溶解物和其他雜質(zhì)濃度維持在可接受范圍內(nèi)而排出的循環(huán)水量 蒸發(fā)損失 C O C 1 8 LiquidGas L G Ratio液氣比 Ratiobetweenwaterandairmassflowrates水與空氣的質(zhì)量流量之比Heatremovedfromthewatermustbeequaltotheheatabsorbedbythesurroundingair冷卻水散發(fā)的熱量等于空氣吸收的熱量L T1 T2 G h2 h1 L G h2 h1 T1 T2 T1 hotwatertemp oC 熱水溫度 冷卻塔進(jìn)水 T2 coldwatertemp oC 冷水溫度 冷卻塔出水 Enthalpyofairwatervapormixtureatinletwetbulbtemp h1 andoutletwetbulbtemp h2 冷卻塔進(jìn)口 空氣與水蒸氣混合 溫度對應(yīng)的焓值 h1 與出口溫度 濕球溫度 的焓值 h2 AssessmentofCoolingTowers 41 CoolingTowerProcess冷卻塔工作流程 1 AirEntersat35 DB26 WB空氣35 DB26 WB2 AirLeavesSaturatedat30 8 2 30 8 飽和空氣離開冷卻塔3 EnteringAirEnthalpyis78 5kJ kg3 進(jìn)口空氣的焓值是78 5kJ kg4 LeavingAirEnthalpyis103 9kJ kg出口空氣的焓值是103 9kJ kg5 WaterVaporizedLatentHeatis2430kJ kg11gwaterabsorbs26 7kJheatduringevaporating5 蒸汽的潛伏熱值是2430kJ kg 11g的水吸取26 7kJ的熱量6 AirSensibleheatis26 7 25 4 1 3kJ6 空氣的感熱為26 7 25 4 1 3kJ 17 3g 28 3g L G h2 h1 T1 T2 L G 103 9 78 5 35 30 8 L G 25 4 11 6 05 g g TrainingAgenda CoolingTowers Introduction簡介Typesofcoolingtowers類型Assessmentofcoolingtowers評估Energyefficiencyopportunities節(jié)能方案 EnergyEfficiencyOpportunities Selectingacoolingtower選擇冷卻塔Fills填料Pumpsandwaterdistribution水泵與配水設(shè)備Fansandmotors風(fēng)扇與電機(jī) EnergyEfficiencyOpportunities 1 Selectingacoolingtower選擇冷卻塔 Capacity冷卻塔容量Heatdissipation kCal hour 散熱量 kCal hour Circulatedflowrate m3 hr 循環(huán)水流量 m3 hr Otherfactors其它因素 EnergyEfficiencyOpportunities Range冷卻水溫差Rangedeterminedbyprocess notbysystem冷卻水溫差取決于換熱過程而不是設(shè)備Approach冷幅Closertothewetbulbtemperature Biggersizecoolingtower Moreexpensive越接近濕球溫度 更大的冷卻塔 更多的投資 1 Selectingacoolingtower EnergyEfficiencyOpportunities HeatLoad熱負(fù)荷Determinedbyprocess決定于換熱過程Requiredcoolingiscontrolledbythedesiredoperatingtemperature合適的工況下才能保證需要的冷量Highheatload largesizeandcostofcoolingtower熱負(fù)荷大 更大的冷卻塔與更多的設(shè)備費(fèi)用 1 Selectingacoolingtower EnergyEfficiencyOpportunities Wetbulbtemperature considerations 關(guān)于濕球溫度Wateriscooledtotemphigherthanwetbulbtemp冷卻水出水溫度高于空氣濕球溫度Conditionsattowersite冷卻塔坐落位置的具體情況Nottoexceed5 ofdesignwetbulbtemp濕球溫度不可高于設(shè)計(jì)濕球溫度的5 及以上ThedesignedwetbulbtempisrefertoambientWB preferred orinlet此濕球溫度指的是環(huán)境濕球溫度 推薦 或者空氣入口處濕球溫度Cantowerdealwithincreasedwetbulbtemp 冷卻塔能否適應(yīng)較高的濕球溫度 Relationshiprange flowandheatload溫差 流量與熱負(fù)荷的關(guān)系 Rangeincreaseswithincreased 以下兩項(xiàng)增加的情況下溫差會(huì)增大 Amountcirculatedwater flow 循環(huán)水量 流量 Heatload熱負(fù)荷Causesofrangeincrease溫差增大的原因如下 Inletwatertemperatureincreases進(jìn)水溫度升高Exitwatertemperaturedecreases出水溫度降低Consequence largertower冷卻水溫差增大 更大的冷卻塔 Wetbulbtemperatureinfluenceonchillerperformance濕球溫度對機(jī)組運(yùn)行的影響 Loweringcondenserwaterimpactonchillerimprovement冷卻水溫下降對機(jī)組性能的影響 0 56DegC Loweringcondenserwaterimpactoncoolingtower冷卻水溫下降對機(jī)組性能的影響 3 9DegC Gettemperaturedatafromcustomer用戶提供的濕球溫度變化圖 WB 26DegC 337DaysWB 26DegC 27Days EnergyEfficiencyOpportunities Hotwaterdistributedoverfillmediaandcoolsdownthroughevaporation熱水經(jīng)過配水設(shè)備流經(jīng)填料介質(zhì) 蒸發(fā)降溫Fillmediaimpactselectricityuse填料介質(zhì)影響冷卻塔用電量Efficientlydesignedfillmediareducespumpingcosts高效填料介質(zhì)可以節(jié)約管路投資Fillmediainfluencesheatexchange surfacearea durationofcontact turbulence填料介質(zhì)影響換熱效率 表面積 接觸時(shí)間與湍流 2 Fillmedia填料 EnergyEfficiencyOpportunities Comparing3fillmedia filmfillmoreefficient比較三種填料介質(zhì) 水膜填料效率最高 2 Fillmedia填料介質(zhì) EnergyEfficiencyOpportunities Pumps seepumpssession水泵