Yankee-Coating-Coverage-Optimization--翻译资料PPT课件

1 OptimizeYankeeCoatingSetup DraftedinMay2010ModifiedinDecember2012 最佳烘缸涂布设计 2 Contents OptimalSprayCoverage 最佳覆盖率 OptimalDropletSize 最佳喷雾颗粒 OptimalEvaporativeLoad 最佳蒸发负载 OtherConsiderations 其它因素 3 HowSprayCoverageWorks 喷淋涂层如何建立 2 3ofvolumeisinthe1 3centerofthesprayarea2 3的喷涂量在中间1 3的喷涂区域Howsprayfansoverlapdetermineswhetherthecoatingisevenornot扇形喷淋重叠如何决定涂层均匀与否 Dec 2012 4 Singlecoverage 0 ofafanareaoverlapsbyitsadjacentone单层覆盖 相邻的扇形覆盖区域没有重叠部分 5 Doublecoverage 50 ofafanareaoverlapsbyitsadjacentone双层覆盖 相邻扇形区域有50 的重叠面积 6 Doublecoverage 50 ofafanareaoverlapsbyitsadjacentone双层覆盖 相邻扇形区域有50 的重叠面积 7 Doublecoverage 50 ofafanareaoverlapsbyitsadjacentone双层覆盖 相邻扇形区域有50 的重叠面积 8 Triplecoverage 67 ofafanareaoverlapsbyitsadjacentone三层覆盖 相邻的扇形覆盖区域有67 的重叠面积 9 Tripleoverlap 67 ofafanareaoverlapsbyitsadjacentone Dec 2012 10 50 VolumetricDistributionofSprayNozzle Dec 2012 11 VolumetricDistributionSprayCoverage TripleCoverage 50 Overlap SprayPattern 30 40 20 0 1 10 9 5 13 17 21 25 29 12 Whatifdistanceorpressurechange 喷淋距离或者压力的变化会产生何种影响 Tooclose coverageisnegative太近 涂层不好TooFar penetrationisdrasticallyreduced太远 喷淋的穿透力大幅度的降低 Optimal Tooclose Toofar 13 Optimal TripleCoverage 67 overlap 最佳涂层 三层覆盖 67 覆盖率 Typeofnozzles喷嘴型号Spacebetweennozzles喷嘴间距DistancefromnozzletipstoYankeesurface喷嘴到烘缸表面的距离Spray barpressure喷射压力 Donotchangeanysinglefactoralone Theyarerelated Changescanonlybemadeinacoordinatedmanner不要单独改变任何一个因素 他们都相互关联 只能同时改变 14 Spray BarRequirement喷射压力要求Smallerdiametertoincreaseflowvelocitybutshouldnotbesmallerthan100mm直径越小 流速越快 但直径不得小于100mm Nozzlespace distancefromtipstoYankeearedeterminedbythedesignofnozzle喷嘴间距及喷嘴到烘缸表面的距离取决于喷嘴的设计 SprayPressure3 4bars喷射压力3 4barWithrecirculationifmachineis3 5morwiderNooscillationneedediftriplecoverage如果是三层覆盖 不需要折动 15 Pressurevs DropletSize压力VS水滴大小Misperception误解Thefasteramachinerunsthehigherthespraypressurehastobe inorderforthespraydropletspenetratethewindagecurtainlayertotheYankeesurface为了使喷雾穿透空气阻力到达烘缸表面 纸机车速越快 喷射压力必须要大 16 Pressurevs DropletSizeTheFact事实上Themomentum massxvelocity determinestheabilityofdropletstopenetratethewindagecurtainlayertotheYankeesurface动量 质量 速度 决定了喷雾穿透空气阻力到达烘缸表面的能力Dropletsizedecreasesandvelocityincreaseswhenspraypressureincreases 压力增加时 水滴变小 速度增加 17 Pressurevs DropletSizeACaseStudySprayP bar37Droplet D um11095Mass kg5 58E 093 58E 09Flow l s0 00650 01Tipvelocity m s19 929 23Initialmomentum 1 11E 071 05E 07kg m sTake awaysdropletmomentumDOESNOTincreasewithpressure水滴冲量不会随压力的增大而增大smallerdropletshasamuchhighermomentumlossinthepath在喷射过程中 越小的水滴 动量流失越大 Dec 2012 18 0 0 002 0 004 0 006 0 008 0 01 0 012 0 014 0 016 0 018 0 02 100 200 300 400 500 700 600 800 NozzleOrificeSize 15DEG 65DEG 95DEG 50DEG MedianVolumeDropletSize 4SPRAYANGLES 100PSI NozzleOrificeSize DropletSize Microns Dec 2012 19 Mixing GoodMixingIsImperativeforStableandEvenCoating良好的混合是建立稳定均匀涂层的必备条件Typicalchemicalcontentis1 1 5 orbelowinspray 化药喷淋的浓度一般为1 1 5 或者更低Thiscanbeensurediftheevaporationloadisnormal如果蒸发负载正常 可以获得良好的涂层Recommendamixingtankwithheatingpriortoinjection在喷淋前 建议加热混合槽Onlinestaticmixerisamustifnomixingtank如果没有混合槽 必须有在线静态混合器 Dec 2012 20 CoatingApplicationSystem Pre mixstyle RecirculationLine Chemicals Water Dec 2012 21 Dec 2012 22 CarryWatervs EvaporativeLoad ToformatackyfilmsuitableforoptimalcrepingaswellasYankeeprotection形成适合最佳起皱同时保护烘缸的黏性涂层Oldergenerationsofcoatingchemicalswillformthefilmonlywhentheyaredried早期化药在完全干燥后才会形成涂层Somenewonescanstartcrosslinkduringthedryingprocessastemperatureincreasesbytheheat一些新化药会随着温度的升高开始发生交联反应Usedtobe nearlyallcarrywaterhastobeevaporatedatthepointofsheetpickup过去 当纸页被剥离时 几乎所有水分才会被完全蒸发Now itisverycomplicated Itisacase by casesituation现在 情况复杂 需具体分析 Dec 2012 23 CarryWatervs EvaporativeLoad IftoomuchcarrywaterThecoatingwillbewet non tackyoreasilywashedoffbytheincomingsheet如果有太多水分 涂层会很湿 没有黏性 容易被洗掉IftoolittlecarrywaterThecoatingissubjecttoexcessheatandcanstarttooxidize leadingtoa Bakedon coatingwithahard glassysurface oftenlowadhesion lowbulk bladechatter andpinholes如果水分太少 化药涂层温度过高而开始氧化 形成硬且光滑的表面 涂层黏度低 低松厚度 刮刀震动 产生针孔 Dec 2012 24 EvaporativeRate TotalevaporativeRate 总蒸发率 SpraycarrywaterwhichmustbeevaporatedpriortowetpressonthebottomoftheYankee喷淋多余水分需在压榨前被蒸发掉2 Waterinthesheetfromabout35 drynessto97 fromthepickupallthewaytocrepingpoint Thisportionisaidedbythehood normallyupto60 纸页自上烘缸到起皱 干度从35 到97 这部分主要受益于护罩 去除水分几乎达60 YankeeDryer WetPress CoatingSpray Crepe Dec 2012 25 CarryWatervs EvaporativeLoad Whatmuchistoomuchortoolittle 多少是太多或太少 Carrywaterflowisdeterminedbynumberofnozzles itsdesignandthespraypressure喷淋水量取决于喷嘴数量 型号及其喷射压力SprayisnormallyappliedtothebottomoftheYankee andtheevaporationofcarrywatertakesplacebeforesheetpickup喷淋一般安装在烘缸下面 喷淋水的蒸发一般在纸页上烘缸之前Inthisunsheetedarea thesteaminsidedoesallevaporation withnoaidfromhood在无纸区域 蒸汽全用于水分蒸发 并没有借助于护罩 Dec 2012 26 CarryWatervs EvaporativeLoad Whatmuchistoomuchortoolittle CarrywateramountshouldbecompatibletotheYankee sevaporationrate aswellastothecoatingchemistry sothatitsremovalpriortothesheetpickupisappropriate喷淋水总量应该与烘缸的蒸发率及涂层化药相应 所以喷淋水应该在纸页上烘缸之前被蒸发掉 ThisensuresOptimalCrepingControlAndBestYankeeProtection这样可确保最佳的起皱和烘缸保护作用 Dec 2012 27 EvaporativeRate Howtodetermineit 如何确定蒸发率EvaporativerateisadirectindicationofaYankee sdryingcapability蒸发率是烘缸干燥效率的直接指导因素Itisveryhardtodefine 很难被定义Itisnormallyestimatedby通常这样估算Evaporativerate condensingrate 1 5蒸发率 冷凝率 1 5Condensingratecanbemeasured Normallyin250 400kg hr m 2冷凝率是可测的 通常为250 400kg hr m 2Evaporativerateisthus150 250kg hr m 2因此蒸发率为150 250kg hr m 2 Dec 2012 28 EvaporativeRate CondensingRateMeasurementsTAPPIStandard0404 49Stopdischargepump停止出口泵Starttimer开始计时器Trackflashtanklevel记录冷凝水箱液位Usevolumeincrease体积增长Yankeediameter width烘缸直径 宽度Calculatekg hr m 2计算 Dec 2012 29 SpecificEvaporativeLoad Definition Dryingneedforspraywaterfromthenozzletipstillthesheetpickup定义 从喷嘴到纸页上烘缸时干燥所需的喷淋水ACaseStudy SZTM1 2 Yankeewidth烘缸宽度6200mmNo nozzles喷嘴数量25Flowpernozzleat4bar4bar压力时喷嘴流量0 51l minTotalflow总流量12 75l minDwelldistance413mmDwellarea2 56m 2SprayreachingYankee喷淋量80 Specificevaporativeload单位蒸发负载239 01kg hr m 2 Dec 2012 30 SpecificEvaporativeLoad ACaseStudy SZTM1 2 Specificevaporativeload239 01kg hr m 2IntherangewenormallyseeFinalconfirmationshouldbedonebycomparingtothemachinesevaporativerate Dec 2012 31 DryerCoating烘缸涂层 Theroleofwaterchemistryinpipecorrosionhaslongbeenunknown 水化学在管道腐蚀中的作用始终是陌生的Calciumhardnessformsscaleonpipewalls preventingcorrosiveattack 钙硬度在管壁上形成一定数量可以组织腐蚀侵害Withenoughcalciumhardnessandalkalinitythismechanismprotectsyan