船舶锅炉水处理_图文

1、Drew Marine 锅炉水处理Primary Functions of BoilerDrew Marine Water Treatment Program锅炉水处理基本功用To inhibit the corrosion processthroughout the system阻止系统腐蚀To render any scale formingconstituents harmless in the boilerwater防止水垢对锅炉系统的危害To prevent carry-over of solids from theboiler to the power and heating pl

2、antsystem防止锅炉杂质进入加热及动力系统Drew MarineCorrosionScaleDeposits Water Related Problems与水相关的问题Drew Marine Scale Formation水垢的形成Common Water Impurities水中的杂质Calcium 钙Magnesium 镁Silica 硅Drew Marine Principal water-related problems scaling水相关问题水垢Scaling is the formation of a crystalline, interlocked layer of mi

3、neral substances on heat transfer surfaces水垢是矿物质在传热面上形成的结晶层Severe scaling normally typically occurs only within the boiler 严重的水垢问题多出现于锅炉内Typical scale formed are predominantly acarbonate/sulfate complex of Calcium and magnesium典型的水垢均为钙,镁离子与碳酸,硫酸离子的复杂化合物Calcium carbonate CaCO3Magnesium sulfate MgSO4

4、Principal water-related problems scaling水相关问题水垢If unchecked, scaling will lower boiler efficiency 若不加以关注,水垢将会降低锅炉效率It will retard heat transfer 阻止热传导Eventually scale buildup will cause the tubes to overheat and rupture 更有可能造成水管过热及损坏 Scale can also accelerate corrosion 水垢也可能加重腐蚀 Scales 水垢Calcium Carb

5、onate Ca(HCO 32CaCO 3+ CO 2+ H 2OCalcium SulfateCaSO 4+ 2H 2O 4.2H 2O Magnesium HydroxideMgCO 3+ H 2O Mg(OH2+ CO 2Drew Marine Solubility of CaSO4 溶解度表 Heavily Scaled-TubeDrew Marine严重腐蚀的水管Prone to Under-Deposit Corrosion 沉积物下腐蚀Drew Marine Scale and Iron Oxide Mixtures水垢与氧化铁的混合Drew Marine Heavily Sca

6、led-Tube严重结垢的水管 Temperature Gradient Across Fouled TubeTube Wall Deposit Temperature of Saturated Steam Temp Tube Wall Deposit Heat Input Concentration Gradient Across DepositSolids Concentrate at Tube Bulk Water ConcentratesDeposits Insulate Boiler Tubes 结垢使锅炉水管被绝热Deposits insulate tubes andcause o

7、verheating结垢使锅炉水管传热能力降低引起过热 Temp at tube wall is higher than temp across porous deposit管壁温度高于沉积物外侧的温度 Dissolved solids concentrate at tube wall & under deposit corrosion occurs 在管壁处出现溶解颗粒浓度及沉积物下腐蚀Bulk Steam Water Mixture 沉积物下腐蚀Once there is a deposit or scale, cathode and anode polarity cell can

8、 be set-up一但出现沉积物,就伴随着微阴,阳极单元的出现。And the metal under the deposit will be anodic 沉积物下的金属即为阳极Oxygen present in the boiler water will accelerate corrosion 氧的存在加速了腐蚀的发生Anodic Reaction阳极反应Fe0Fe+ 2eUnder-Deposit Corrosion沉积物下腐蚀Under-depositCorrosionProfile View ofDrew Marine Under Deposit CorrosionUnderDe

9、positCorrosionPrincipal water-related problemsDrew Marine sludge 水相关问题淤泥Sludge may be a combination of any suspended materials in the water, and it includes:淤泥包括水中各类悬浮物:Loose corrosion products, insoluble mineral precipitates and oil松散的腐蚀物,不可溶矿物质及油Significant proportion of suspended material are gen

10、erated outside the boiler锅炉外产生的悬浮物占了较大部分Oil contamination 油污染Drew Marine Principal water-related problemssludge 水相关问题淤泥“Baked-on sludge”on heat transfer surface acts as a heat insulator 固化的淤泥影响热传导Excessive sludge loading from outside boiler may distorts the relationship of suspended to soluble const

11、ituents of the boiler water过量的外来悬浮物会影响炉水中的可溶物This will render in-built program controls less effective 以至影响水处理程序的效果Liquid Coagulant -Sodium Carboxymethylcelluloseto bring sludges to low point to be blown-down. Liquid Coagulant 可对淤泥进行处理,使之容易被排污排出Principal water-related problemsDrew Marine corrosion 水

12、相关问题腐蚀4 main categories of corrosion which will damage a boiler/feed system if left unchecked are:4种有害于锅炉的腐蚀形式Mineral acid corrosion -mostly in boiler矿物腐蚀主要发生在锅炉内Carbonic acid corrosion -mostly in thecondensate碳酸腐蚀主要发生在冷凝器Oxygen corrosion -most severe in boiler氧腐蚀主要发生在锅炉内Differential concentration (

13、crevice corrosion -缝隙腐蚀主要发生在锅炉内 Principal water-related problemsmineral acid corrosion 水相关问题矿物酸性腐蚀Seawater ingress, condenser inleakage and/or distiller carryover creates mineral acids in the boiler 海水侵入,冷凝器渗漏及造水机泄露均会造成矿物酸性腐蚀Mineral Acid corrosion 矿物酸性腐蚀Fe + 2HCl = FeCl 2 + H 2Maintain “P ”alkalinit

14、y between 100 -150 ppm and “T ”alkalinity less than 2 “P ”alkalinity or pH 10.8 -11.0 维持酚酞碱度在100 150 ppm ,总碱度低于2倍酚酞碱度或PH 10.8-111234567891011121314Theoretical Corrosion RateCorrosive Action Under Normal Boiler ConditionsEffect of High Oxygen ContentGeneral WastagePitting AttackIncreased FoamingI s o

15、 l a t e d P i t t i n g R e c o m m e n d e d A l k a l i n i t yEffect Of pH On The Rate Of CorrosionpH 值于腐蚀率关系Drew MarineAcidity, Alkalinity and pH Ranges酸,碱pH 值Free Mineral Acidity (FMACO 2escapes quickly into environment5000mg/l500505Bicarbonate AlkalinityFree CO 2GasAcidity mg/l CaCO 255050050

16、00mg/lOH Alkalinity mg/l CaCO 2Carbonate AlkalinityHydroxyl AlkalinityM e t h y l O r a n g e E n d p o i n tN e u t r a l i y H = O H“M ”P h e n o l p h t h a l e n E n d p o i n t“P ”pHPrincipal water-related problemsoxygen corrosion 水相关问题氧腐蚀Direct corrosive attack on boiler steel by oxygen occurs

17、 by cathodic depolarization of electrochemical cells at the metal/water interface 在水与金属的界面上,氧参与微电化腐蚀阴极,直接侵蚀锅炉铁质Most low pressure systems subjected to atmospheric oxygen ingress 大多数低压锅炉中均受到氧的侵入Keep cascade tank temperature as high as possible 保持尽量高的热水井温度Reduce the remaining dissolved oxygen with an o

18、xygen scavenger 用除氧剂消除残余氧份 Effects of Oxygen Corrosion氧腐蚀的危害Most severe in boiler在锅炉内较为严重Metal ions Precipitate as Oxides金属转化为氧化物Reduce Heat Transfer 阻隔热传导Lower than rated capacity降低锅炉产量Equipment Failures 导致设备失效Repair, and Replacement 增加维修及更新费用 Oxygen Corrosion Control氧腐蚀控制Mechanical Pre-treatment机械

19、除氧Chemical to scavenge the remaining dissolved oxygen用化学剂驱除剩余氧份Drew Marine1284-121436688110Temperature in Degrees CentigradeOxygen Content ml per literSolubility Of Oxygen In Water氧在水中溶解度与温度的关系At Atmospheric PressureCorrosion rate,mm per year penetration24681049°C 32°C 9°C Effects Of

20、Oxygen Concentrations氧浓度与腐蚀率关系Mild effect at low temp Increasing temperature increases corrosion rate Corrosion 氧腐蚀Oxygen PittingOxygen CorrosionDrew Marine Corrosion氧腐蚀Occurs in anypart of steamPitting generatingsystem 可能出现在蒸汽系统任何部位Readilyrecognized bysharp-edgedpits其特征为边缘比较锋利Drew Marine Oxygen Pit

21、ting Drew Marine Principal water-related problemscarbonic acid corrosion 水相关问题碳酸腐蚀Carbonic acid is formed when CO2 dissolve in the condensate 二氧化碳溶于凝水,形成碳酸腐蚀CO2 is generated by the thermal breakdown of bicarbonates in seawater ingress二氧化碳源自于有机物分解Carbonic Acid corrosion 碳酸腐蚀CO2+ H2O = H2CO3Cu+ + H2CO

22、3= CuHCO3+ H+Fe + 2H2CO3 = Fe(HCO32+ H2Feeding and recycling of a neutralizing amine投放中和剂进行中和Drew Marine Results of Low Condensate pHCondensate System CorrosionpH值低引起的冷凝系统腐蚀GroovingThinningDrew Marine Carbonic Acid CorrosionLow pH CorrosionDrew Marine Different Type Treatment Programs for Low &

23、MediumPressure Boilers中低压锅炉不同类型的处理程序Drew MarineLP BWT Programs低压锅炉水处理剂程序Drew Standard Boiler Treatment Program标准锅炉水处理剂程序Drew AGK-100 Boiler & FeedwaterTreatment program AGK-100锅炉水处理剂Drewplex AT and OXDrewplex AT and AmerzineDrew Marine BWT Program Selection Criteria锅炉水处理剂程序选择准则Drew Marine Some S

24、election Criteria选择准则Quality of make-up water 补给水质量Quantity of make-up water daily日常补给水数量After-boiler distribution network锅炉后管路系统Dosing and testing simplicity投药及化验的简便性Drew Marine Low & Medium PressDrew Marine Boiler Treatment Program中低压锅炉标准处理程序Alkalinity Control 碱度控制GCHardness Control 硬度控制Adjunc

25、t -BOxygen Scavenger/Corrosion Inhibitor 除氧/腐蚀抑制剂AmerzineDrewplex OX -(DEHACondensate Control 冷凝水控制SLCC ADrew Marine Alkalinity Control 碱性控制-Ameroid GCTo raise the boiler water alkalinity, in order to maintain the hydroxyl ion concentration in the optimum range for the formation of goodprotective ma

26、gnetite on the steel surfaces 提高锅炉水碱性,保持烃基离子的理想含量,有利于钢表面形成保护膜。Fe + 2NaOH Na 2FeO 2+ H 2Na 2FeO 2+ 4H 2O 6NaOH + Fe 3O 4+ H 2 And to help in the formation of non -adherent sludge instead of scale when hardness enters the boiler 在硬物进入锅炉时,有利于形成无附着性淤渣而无水垢Drew MarineIt reacts with the bicarbonates and ch

27、lorides of magnesium and calcium; to precipitate harmless non -adherent sludge and sodium chloride which remains in solution 氢氧化钠与重碳酸盐及氯化镁,氯化钙作用,形成无附著性的淤泥和可溶的氯化钠 MgCl 2+ 2NaOH Heat Mg(OH2+ 2NaCl Exposed to Atmosphere, NaOH absorbs CO 2to form NaCO 3氢氧化钠将吸收大气中的二氧化碳形成碳酸钠Alkalinity Control 碱性控制-Ameroid

28、 GCDrew Marine Hardness Control硬度控制-Adjunct BTo provide a phosphate reserve in boiler 提供在锅炉中磷酸根的含量To precipitate calcium as calcium phosphate, a soft non-adherent sludgethat can easily be blowdown使钙形成磷酸钙,无附着性,容易排污The carbonates, sulfates and other ions combine with sodium and remain insolution碳酸,硫酸及

29、其他离子和钠生成可溶解物Drew MarinePhosphate Hide-outphenomenon磷酸根隐藏现象This phenomenon is characterized by,Abnormally fast loss of phosphate residual from boiler water during normal steaming 此现象表现为,在正常运行中磷酸根残留浓度反常地迅速变小And re-occurrence of a high phosphate residual when shut down or operated at a low steaming rat

30、e在停炉或蒸汽产量低时,磷酸根残留浓度又出现了This due to the relatively limited solubility of sodium phosphate compounds at high temperature 归因于高温下的磷酸钠的相对低溶解性Drew MarineIn a dirty boiler, the concentrating effect is great enough that the sodium phosphate forms a dry salt in the deposit 在较脏锅炉中,磷酸钠盐会浓缩沉积成固态盐 When the heat

31、on surfaces with hide -out is reduced or removed this salt dissolves in the boiler water 当表面热量减少时,该沉积盐会溶解回锅炉水中Phosphate Hide-outphenomenon磷酸根隐藏现象Drew MarineCorrosion Inhibitor/Oxygen ScavengerAmerzine 除氧抑蚀剂To scavenge the residual dissolved oxygen 消除溶解氧It also reacts with Ferric Oxide (Fe 2O 3 to fo

32、rm black magnetite, Ferrous Oxide (Fe 3O 4 which retards corrosion 它也会与Fe 2O 3反应生成Fe 3O 4而阻止腐蚀It also converts the Cupric Oxide (CUO on condenser tubes to the protective Cuprous Oxide CU 2O film 在冷凝管使CUO 转化为保护性的CU 2O Disadvantage -identified as a Carcinogen 弱点-可能致癌Drew Marine Hydrazine Properties 联氨

33、特性Hydrazine reacts very slowly at <1350C to form nitrogen and water在<1350C 时联氨缓慢反应成氮和水Hydrazine optimal activity temperature is approximately 1770C联氨的理想温度为1770CAt above 2040C, hydrazine can decompose to form nitrogen, hydrogen and ammonia在2040C,联氨会分解成氮,氢和氨。Ammonia gives good corrosion protecti

34、on to copper & copper alloy components of the system in the absence of dissolved oxygen在没有溶解氧的情况下,氨对铜和铜合金有很好的防腐作用DiethylhydroxylamineDrew Marine 最新除氧剂Drewplex OXVolatilizes & transported by steam throughout the boiler & condensate system通过蒸汽在锅炉和冷凝系统中挥发输送Provides ferrous and non-ferrous m

35、etal passivation in pre-boiler, boiler and after boiler sections在锅炉中使铁及其他金属钝化Good oxygen scavenger良好的除氧剂Does not add dissolved solids to boiler water不会在锅炉水中增加溶解颗粒Low toxicity低毒性Drew MarineOther Means toScavenge Oxygen 其他除氧方式Deaerator除氧器Maintain cascade tank temperature as high as possible without losing pump suction尽量维持热水井高温Water at 100C at atmospheric pressure usually contains between 8 to 10 mg/liter (ppm