鍋爐培訓(xùn)資料NEW

1、GE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Boiler Water TreatmentTechnical TrainingGE Power & WaterWater & Process Technologies貴廠鍋爐現(xiàn)狀貴廠鍋爐現(xiàn)狀今天現(xiàn)場分析，發(fā)現(xiàn)如下問題：今天現(xiàn)場分析，發(fā)現(xiàn)如下問題：1、爐水、爐水PH 8.98，偏低，國標(biāo)為，偏低，國標(biāo)為9.011.0，正?？刂埔话阍?，正?？刂埔话阍?.510.5；2、爐水、爐水Fe含量超標(biāo)（含量超標(biāo)（0.69ppm）；）；危害：過低的危害：過低的P

2、H會造成鍋爐腐蝕，產(chǎn)生爆會造成鍋爐腐蝕，產(chǎn)生爆管現(xiàn)象；管現(xiàn)象；解決方案：采用協(xié)調(diào)磷酸鹽控制爐水解決方案：采用協(xié)調(diào)磷酸鹽控制爐水PH， 防止腐蝕防止腐蝕GE PROPRIETARY & CONFIDENTIAL GE Power & WaterWater & Process Technologies貴廠鍋爐現(xiàn)狀貴廠鍋爐現(xiàn)狀3、過熱蒸汽、過熱蒸汽SiO2含量高達(dá)含量高達(dá)296ppb，飽，飽和蒸汽和蒸汽SiO2含量高達(dá)含量高達(dá)140ppb，國標(biāo)控制，國標(biāo)控制要求為要求為20ppb，嚴(yán)重超標(biāo)，嚴(yán)重超標(biāo) ；危害：蒸汽中危害：蒸汽中SiO2含量超標(biāo)，會在汽輪機含量超標(biāo)，會在汽輪機等表面形成硅酸鹽垢，難以清

3、洗，會嚴(yán)重等表面形成硅酸鹽垢，難以清洗，會嚴(yán)重影響設(shè)備的穩(wěn)定運行，增加運行能耗影響設(shè)備的穩(wěn)定運行，增加運行能耗解決方案：解決方案：1、加大排污；、加大排污； 2、檢查混床；、檢查混床；GE PROPRIETARY & CONFIDENTIAL GE Power & WaterWater & Process Technologies貴廠鍋爐現(xiàn)狀貴廠鍋爐現(xiàn)狀4、鍋爐除氧器目前采用的是熱力除氧，、鍋爐除氧器目前采用的是熱力除氧，經(jīng)現(xiàn)場測試，溶解氧超出了儀器測試范圍經(jīng)現(xiàn)場測試，溶解氧超出了儀器測試范圍（40ppb），通過試樣顏色預(yù)估在），通過試樣顏色預(yù)估在100ppb左右（國標(biāo)左右（國標(biāo)15ppb，正

4、?？刂?，正?？刂?0ppb）；）；危害：過高的氧進(jìn)入鍋爐，會造成氧腐蝕，危害：過高的氧進(jìn)入鍋爐，會造成氧腐蝕，進(jìn)而會發(fā)生鍋爐爆管。進(jìn)而會發(fā)生鍋爐爆管。解決方案：解決方案：1、加強熱力除氧控制；、加強熱力除氧控制； 2、增加化學(xué)除氧；、增加化學(xué)除氧；GE PROPRIETARY & CONFIDENTIAL GE Power & WaterWater & Process Technologies貴廠鍋爐現(xiàn)狀貴廠鍋爐現(xiàn)狀5、鍋爐凝結(jié)水、鍋爐凝結(jié)水Fe含量含量0.69ppm，嚴(yán)重超，嚴(yán)重超標(biāo)（國標(biāo)標(biāo)（國標(biāo)0.1ppm）；）；危害：蒸汽未處理，造成凝結(jié)水危害：蒸汽未處理，造成凝結(jié)水PH偏低，偏低，腐蝕

5、設(shè)備管道，而且過高的凝結(jié)水腐蝕設(shè)備管道，而且過高的凝結(jié)水Fe含量含量會帶入鍋爐，會進(jìn)一步對鍋爐產(chǎn)生腐蝕，會帶入鍋爐，會進(jìn)一步對鍋爐產(chǎn)生腐蝕，影響鍋爐的穩(wěn)定運行。影響鍋爐的穩(wěn)定運行。解決方案：解決方案：1、投加中和胺，調(diào)整蒸汽、投加中和胺，調(diào)整蒸汽PH； 2、如果條件允許，增、如果條件允許，增加凝結(jié)水加凝結(jié)水 精處理裝置；精處理裝置；GE PROPRIETARY & CONFIDENTIAL GE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Boiler Water TreatmentObjecti

6、vesPrevent Corrosion cause byAcidic pH (12.5)Dissolved Oxygen in BFWPrevent Deposition cause byCorrosion products (iron/copper oxides)Insoluble minerals salts (Ca/Mg/SiO2)Maintain Steam PurityImpurities in steam may poison process catalystMinimizes boiler water carryoverGE Power & WaterWater & Proce

7、ss TechnologiesGE PROPRIETARY & CONFIDENTIAL Demin H2OCondensateBFW Steam DrumC-6130DeaeratorC-8108EO ReactorE-6101EO ReactorCoolerE-6104MP Steam 16 MPaE-8129EOEthylene + O2LP SteamEO Waste Heat Boiler SchematicHP2650PO4NA0880AmineOS7785O2 ScavBlowdownpH/CondPO4/SiO2pH/CondSiO2/D. O2/FepH/Cond/SiO2p

8、H/Cond/SiO2pH/Cond/FeProcess75.4 MT/Hr8.6 MT/Hr2.4 MT/HrProcessGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Boiler CorrosionGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Low pH CorrosionBoiler metallurgy typically is made of carbon steelAt wat

9、er pH 12.5 is corrosive to carbon steelSuch high pH can occur due to concentration of free caustic (NaOH) on steam generating heat transfer surfaces (eg, boiler riser tubes) to 2000 ppm under certain operating/design condition (high heat flux/low flow/water steam 2-phase flow)GE Power & WaterWater &

10、 Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Causes of High pHNaOH contamination in boiler make up water or condensate return NaOH leak from demin water plantNaOH or KOH contamination in condensate from process leakLocalized concentration of free NaOH due to high heat flux or steam blanketingG

11、E Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL CorrosiveCorrosiveHIGH OR LOW BOILER WATER pH CORRODES BOILER STEEL8.5 pH12.7 pHpHRelativeCorrosiveAttackSafe Range 1 2 3 4 5 6 7 8 9 10 11 12 13 14GE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Disso

12、lved O2 CorrosionAt temp 100 C, dissolved O2 in water can cause O2 pitting corrosionO2 pitting corrosion is very rapid and as such, it can cause tube leak in relatively short timeTo eliminate dissolved O2 corrosion in a boiler system (feed water/boiler water/condensate) dissolved O2 must be removed

13、and maintained at less than 10 ppbGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL pH Control to Minimize CorrosionBoiler feed water and condensateUse of volatile neutralizing amines, Steamate NA0880Boiler WaterAlkaline PO4, OptiSperse HP2650Stainless steel metallurgy is res

14、istance low/high pH and dissolved O2 corrosionGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Dissolved O2 RemovalMechanical deaeration in deaerator Raise boiler feed water temp to 1-2 C of saturation temperature by steam strippingRemove dissolved O2 to 12.5Attacks Fe3O4Hea

15、tFlowBoiler Tube wallGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL PREVENTING CAUSTIC CONCENTRATIONNaOH + Na2HPO4Na3PO4 + H2O CausticDisodiumPhosphateTrisodiumPhosphateWaterv Maintain clean heat transfer surfaces v Proper control boiler cycles/blowdownvControl boiler wate

16、r Na/PO4 ratio at 2.3 - 2.8 (coordinated or congruent pH/PO4 treatment)GE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Elimination of Localized Caustic Concentration Cell by Coordinated pH/PO4 Treatment (OptiSperse HP2650)NaOH neutralizedBy Na2HPO4HeatFlowGE Power & WaterWa

17、ter & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Localized concentration of acidLocalized Concentration of Acid Results in Low pH Corrosion Can Occur When PO4 is 3 ppmCl-Cl-Cl-H+H+H+Cl-H+pH = 8.0HeatGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Shell & Tube Waste H

18、eat Boiler Water in shellside, Process gas (850 C) in tube sideLocalized corrosion on shellside due to acid concentrationGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL DepositionGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Boiler DepositionCaus

19、es of boiler deposition Precipitation of insoluble mineral salts such as CaCO3, CaSO4, Mg(OH)2, Mg Silicate originating from boiler make-up water or cooling water contaminationCorrosion products such as iron/copper oxides from condensate returnDeposition tendency increases with increasing boiler ope

20、rating pressure due to higher boiler tube skin temperaturesGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Prevention of DepositionMineral SaltsDemineralization of boiler make-up water using reverse osmosis and ion exchange resinsRemoves 99.9% of ionic dissolved solidsCondu

21、ctivity 0.2 us/cmSiO2 8.8, dissolved O2 7 ppb)Install condensate filtration/polishingControl BFW total Fe 20 ppb, Cu 5 ppbBoiler blowdown control ( 1- 2 %)GE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Steam PurityGE Power & WaterWater & Process TechnologiesGE PROPRIETARY

22、& CONFIDENTIAL Steam PurityControls by steam separating equipment design (demister/cyclones), operating condition (drum level/pressure control) and boiler water chemistry (SiO2, Conductivity, pH)Impurities in steam come from boiler water carryover (mechanical and volatile)Typical mechanical carryove

23、r at 16 MPa steam drum pressure is 0.05% of boiler water dissolved solids SiO2 causes volatile carryover - increases with increasing SiO2 in boiler water, increasing steam drum operating pressure and reducing boiler water pHSaturated steam purity control limitsNa 10 ppb, SiO2 8.8, reactivity increas

24、es with increasing pHGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Steamate NA0880Feed RateTypical 2 - 5 ppm of boiler feed waterDecreases with increasing % unpolished condensate returnIncreases with increasing pH control3x increase in product feed rate at BFW and Steam p

25、H = 8.8 versus pH = 9.2Therefore, accurate pH measurement is importantFeed PointIdeally deaerator drop-leg or storageProvides boiler feed water pH elevation to minimize corrosion in preheaters and improve CorTrol OS7785 reactivity with dissolved O2GE Power & WaterWater & Process TechnologiesGE PROPR

26、IETARY & CONFIDENTIAL Steamate NA0880Volatility (Distribution Ratio)NA0880 is a blend of two neutralizing amines with different distribution ratioThis allows optimum distribution of amines throughout the entire condensate systemSpecific conductivity BFW/steam/condensateNA0880 contributes to BFW/stea

27、m/condensate specific conductivity Increasing NA0880 feed rate increases pH and specific conductivity of BFW/steam/condensateGE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL OptiSperse HP2650 Feed RateProportionate to boiler blowdown rate and PO4 residual as outlined below * Based on boiler feed water flow rateFeed point Ideally to steam drum and diluted to 10 to 20 times with demineralized waterBlowdown (%) Boiler PO4 (ppm) HP2650 (ppm) *1102.22104.4252.2GE Power & WaterWater & Process TechnologiesGE PROPRIETARY & CONFIDENTIAL Boiler