7f issue 3 fac link

7/28/2019 7F Issue 3 FAC Link

1/7COMBINED CYCLE JOURNAL, Second Quarter 2004 1

FLOW-ACCELERATED CORROSION

FAC and cavitation:Identification,

assessment,monitoring,prevention

By Dr Otakar Jonas, PE, Jonas Inc

Flow-accelerated corrosion (FAC), alsocalled erosion/corrosion, and cavitation are

significant and costly damage mechanismscommon to all types of utility and indus-trial steam cycles. There has been an increasedemphasis on correcting these problems because ofrecent fatal accidents and costly material damage.

In combined-cycle (CC) plants, thinning of pipeand damage to system components made of carbonand low-alloy steel typically occur in the feedwaterand wet-steam sections of the cycle. Experts esti-mate that more than half of all CC units have FACin the heat-recovery steam generator (HRSG) andelsewhere. Sufficient knowledge exists to predictand prevent these two types of damage. However,

designers and plant operating staffs must be proac-tive to avoid it.FAC is a mass-transfer process in which the pro-

tective oxide (mostly magnetite) is removed from thesteel surface by flowing water. Material wear ratedepends on (1) steel composition, temperature, flowvelocity and turbulence, (2) water and water-droplet

pH, and (3) the concentrations of both oxygen andoxygen scavenger. These complex relationships areidentified in Fig 1. Fig 2 shows the impact of pipingand component geometry. Most of the above factorshave strong, exponential effects on the materialwear rate, as Figs 3 thorough 7 indicate.

The FAC problem is most pronounced in carbonsteels. In these materials, even small concentra-tions of chromium, molybdenum, and copper canimprove FAC resistance. A survey of 38 heats of car-bon steel found that, depending on the scrap com-position, there could be up to 0.3% Cr, which mayimprove FAC resistance by up to 100-fold. WhereFAC problems cannot be resolved by changingwater chemistry, carbon steels often are replacedby low-alloy steels, such as P11 and P22or a weld-deposited overlay is used.

Temperature has a pronounced effect on the FACwear rate (Fig 4) and when a system is inspected,

components in the 250-400F range get a prior-ity. Flow velocity (Fig 5) has a strong effect, whichmakes wet steam systems very susceptible to FAC.Reason is that the velocity of the steam usually ismuch higher than that of the water.

Water chemistry effects on FAC often are notwell interpreted. The pH of feedwater and steamdroplets must be kept above a certain threshold,which depends on the pH agent used (Fig 6) and ontemperature. For ammonia and amines, their effectdiminishes with temperature. For feedwater treat-ment with ammonia, a room-temperature pH above9.5 is desirable.

Oxygen actually is good for preventing FAC.Experience indicates that 5 ppb of oxygen in feed-water can practically stop FAC, while excessiveconcentration of oxygen scavengers accelerates it.In most CC units that do not have copper-alloy tub-ing, oxygen concentrations can be as high as 20 ppbwithout causing any problems.

TL = F(x), FG, FT, FC, FR

Steel composition factor

Water treatment factor (pH, etc)

Temperature dependence factor

Geometry factor

Mass-transfer dependence function

Thickness loss rate

1. Material wear rate depends on many variablesincluding steel composition, oxygen concentration,

flow velocity, temperature, etc (above)2. Component shape impacts FAC, (right) with highernumbers in chart above signifying a stronger influence

kc = 1 kc = 1 kc= 1 kc = 0.75

kc = 0.6 kc = 0.52 kc = 0.3 kc = 0.23

kc = 0.15 kc = 0.15 kc = 0.16 kc = 0.04

kc = 0.16 to 0.24


2/7

2 COMBINED CYCLE JOURNAL, Second Quarter 2004


FAC experienceThough FAC control programs have been imple-mented in all US nuclear plants, and in many fos-sil-fired utility and industrial plants, major dam-age still occurs, as several references listed at theend of this article attest. This is particularly true atCC units, as noted earlier, generally for one or more

of the following reasons:Limited experience in the design, construction,and operation of CC plants by many OEMs, archi-tect/engineers, and owner/operators.

Imperfect technical toolsthat is, softwareforquantifying the effects of temperature, oxygen scav-engers, cavitation, and water chemistry on FAC.Misrepresentation of water-chemistry his-tory and material compositions, leading to grosserrors in FAC assessment.

Any carbon- or low-alloy-steel component or pip-ing system at a CC plant is a candidate for FAC.These include:

Single-phase systemsHRSG economizers,headers, drum liners, boiler tubes, and feedwa-ter pipes in drums; condensate/feedwater; aux-iliary feedwater, heater, and other drains; pumpglands and recirculation lines.Two-phase systemslow-pressure (l-p) tur-bine wet-steam extraction sections and pipes,glands, blade rings, casing, rotors, and disks;flashing lines to the condenser (miscellaneousdrains); feedwater-heater vents, shells, and sup-port plates; feedwater heaters; HRSG moistureseparators; condenser shell and structure.

Where to look for FACHRSGs. Typical locations of FAC damage inHRSGs is shown in Fig 8. It occurs in (1) areas of

high turbulence, such as in the transitions fromvertical generating tubes to headers and drums; (2)economizers and l-p drum circuits which often oper-ate in the peak temperature range, and (3) down-comers, particularly the lower-header areas whereFAC can be combined with cavitation.Use of sodium phosphate boiler-water treatmentcan prevent FAC in HRSGs. However, in CC

designs where the l-p boiler serves as a heater forthe intermediate-pressure (i-p) and high-pressure(h-p) boilers, it cannot be used. Reason: Phosphatewould concentrate in the i-p and h-p boilers andcause other problems.

Feedwater piping. Most frequently, FAC dam-age is found in feedwater piping with the piping-component geometry effect following the classifica-tion index shown in Fig 2. There have been at leastthree fatal accidents caused by ruptures of thinnedpipes, none reported in combined cycles.

Deaerators. FAC thinning of deaerator piping,partitions, and liners, and of the deaerating vesselitself in the water outlet and steam inlet areas, areexperienced occasionally.

Condensers. Exhaust steam leaving the l-pturbine can contain from 5 to 10% moisture and thewet-steam velocity at the exit of the last row bladesis hundreds of feet per second, an ideal environ-ment for FAC. Also, the moisture-droplet pH oftenis suppressed. There have been many cases of con-denser-support-structure FAC, and the iron oxidesproduced by this process are a major impurity incondensate.

Return condensate from various processes oftenis contaminated with organic and inorganic impuri-ties and carbon dioxide, which reduces its pH andincreases the likelihood of FAC. To avoid problems,make provision for automatic dumping of bad conden-sate or for condensate purification by ion exchange.

Mo steel1

Carbon steel2

Carbon steel2 +500 m Metco 33

Carbon steel2+ 500 m nickel

18Cr stainless steel

13Cr stainless steel

2Cr-1Mo steel3

1Cr-Mo steel4

Cr-Mo-Ni-V steel

Ni-Cr-Mo-V steel

Ni-Cu-Mo-Nb steel

Specific material wear rate, g/cm2-hr

0 10 50 150 200

pH O2 content7 500 g/kg9.5


3/7

COMBINED CYCLE JOURNAL, Second Quarter 2004 3


Feedwater heaters and other heat exchangers.Tubes: Carbon-steel tube bundles, particularly thetube inlets, are among the components most vul-nerable to FAC. Such tubes typically are designedwith the minimum wall thickness necessary to sup-port the mechanical loads because a thinner wallpromotes more efficient heat transfer. Thus evena small reduction in wall thickness caused by cor-

rosion can result in failure. FAC can occur on bothinterior and exterior tube surfaces.On the steam side of feedwater heaters, FAC

attack depends significantly on the design and themoisture content of the steam. Keep in mind thatthe actual moisture content of the steam extractedfrom the turbine can differ from the theoreticalmoisture level because of drainage and other condi-tions that are specific to each turbine.

Vessel: Thinning of the feedwater-heater pres-sure vessel occurs mainly at the steam and drainnozzles and where the flow of wet steam turns.This thinning is caused by direct impingement of

the jet or by the deflected jet after it has struck apoorly designed impingement plate. Impingementof steam moisture has locally eroded feedwaterheater shells almost to perforation in several fos-sil-fired units.

Internals: Feedwater heaters often contain parti-tioned-off areas which serve a specialized heat-trans-fer purpose. These boxes cool the exiting drain flowor desuperheat the entering steam, and are subjectto the same damage mechanismas the vessel. In addition, whenthere are leaks through a boxwall, the secondary flows cre-

ated can cause rapid damage. Indrain cooling boxes, damage canoccur even without leaks if thereis improper control of the conden-sate level.

Heater drains. Major prob-lem areas include the drainlines below the feedwater heat-ers. They often experience prob-lems with level control valves.However, even without valveproblems, these lines frequentlyexperience FAC because the liq-uid is near saturation conditionsand it may flash across the levelcontrol valves. In these loca-tions, FAC could be combinedwith cavitation.

Downstream of flowmeters.The piping immediately down-stream of flowmeters, orifices,and other restrictions has beena source of problems because ofthe increase in local velocity andlocal turbulence, and the suscep-tibility to cavitation.

Downstream of controlvalves. There have been a largenumber of reported instancesof FAC degradation, including

some significant failures, at locations downstream ofcontrol valves.

Thermowells, sampling nozzles, and injec-tion quills. These obstacles to flow can producevortex shedding with locally high velocities lead-ing to small areas of pipe thinning caused by FACor cavitation. Pipe-wall thickness should be mea-sured starting from these obstacles to about three

feet downstream.

How to control FACAn effective FAC control program begins with anassessment of the propensity of different plantsystems and components to FAC, and also includesthe use of available software with water andsteam-chemistry corrections and periodic inspec-tions. Monitoring of iron concentration around thesteam cycle also is useful; elevated concentrationsmay indicate ongoing damage in a specific subsys-tem.

Inspection and NDT. After conducting a theo-retical evaluation of your CC units Rankine cyclefor its propensity to FAC and cavitation attack,select several of the most susceptible componentsfor inspection. The nondestructive examination(NDE) methods typically used include ultrasonicwall-thickness measurement and radiography ofsmall sections of equipment and piping systemswith geometries that can cause turbulence. Inspec-

5000

1000

500

100

50

10

5

1

0.5

Specificmaterialwearrate,

g/cm2-hr

Ni-Cu

-Mo-N

b

1Cr-Mo(A213

GrT12)

2Cr-Mo(A213GrT22)

Flow velocity, ft/sec32.8 65.6 98.4 131.2

Specificmaterialwearrate,g/cm2-hr1000

500

10050

10

5

1

0.5

0.1

1000500

10050

10

5

1

0.5

0.1

6 7 8 9 10 11

pH

Mo (A161 Gr T1)1Cr-Mo(A213 Gr T12)

Carbon steel

580 psig,356F,

128 ft/sec,


4/7

tion grids have been developed to facilitate theultrasonic wall-thickness measurements of typicalgeometrical elements. Often neglected are pipingareas downstream of flowmeters, thermowells, andinjection quills, where both FAC and cavitation canbe active. Keep in mind that vortices generated bythe flow obstruction can travel for many feet.

Many components can be inspected during oper-ation using x-ray techniques. However, if there isan urgency for safety or other reasons to verify thatFAC and/or cavitation damage is not of immediateconcern, and system shutdown is not possible, asuccessful hydro test of at least 50% overpressureoffers sufficient proof.

Software solutions. At least three softwarepackages are available for assessment of wall thin-ning caused by FAC. These have been developed bythe Electric Power Research Institute (EPRI), Palo

Alto, Calif; Electricite de France (EdF), Paris; andSiemens AG, Erlangen, Germany. Results of pre-dictions of FAC with the use of the software havebeen mixed, some realistic, some very wrong. Themain reasons for the wrong predictions includepoor representation of water chemistry in the soft-ware (at-temperature pH, concentration of oxygenscavenger, concentration of oxygen, and chemistryof water droplets), oversimplification of the water-chemistry history, and a failure to use the actualsteel composition.

Cavitation

Cavitation is a repeated generation and collapse ofbubbles (or cavities) in a liquid because of local stat-ic-pressure fluctuations, usually caused by changesin flow velocity. If the pressure of a flowing liquiddecreases to below its vapor pressurefor example,because of significant increases to the local flowvelocitythen vapor bubbles are nucleated. Thebubbles are transported downstream from the flowdisturbance, and when they reach a region of higherpressure, they collapse suddenly and may erode anysolid material in their vicinity.

The phenomenon is predominantly mechanicalin nature, but corrosive environments do acceleratethe damage. Shock-wave emission and jet forma-tion caused by the collapse of individual cavities arethe fundamental factors responsible for cavitation.Tests indicate that the fatigue endurance limit ofthe material is the primary parameter that controlscavitation. Damage occurs to the surface of the com-ponent, just downstream from the cavitation source.Cavitation bubbles are reabsorbed within five to 10pipe diameters. Barring any obstructions or changesin direction, reabsorption is accomplished causingfurther damage. In CC plants, cavitation damagecan occur in pumps, valves, and piping.

The effect of flow on pressure is illustrated inFig 9 for flow through an orifice. Note that in the

Expansion joint

Inlet ducts

Internal insulationand lagging

All: Layup corrosion,weld corrosion cracking

Steam drum:FAC, high carryover

FAC

Integral structural steel

Manway

Downcomer:FAC, corrosion

Expansion joint

Evaporator:low-cycle fatigue,pitting, hydrogen damage

FAC, cavitation

Economizer:FAC, pitting, corrosion

Stack

Outlet duct

Superheater:stress corrosioncracking, exfoliation, creep,low-cycle fatigue

Vena contractaOrifice

Flow

Staticpressure

Inlet (p1)

pvc

pvc

Outlet (p2)

Vaporpressure (pv)

p1p2

8. Typical locations of FAC and other types of damage foundin HRSGs reveal that problems generally occur in regions ofboiler that experience high turbulence (above)

9. Sharp reduction in static pressure causes the productionof vapor bubbles which translates to cavitation attack in com-ponents that experience a high pressure drop (right)




5/7



flow region immediately downstream of the orifice,where velocity is highest, the static pressure dropsbelow the vapor pressure and steam bubbles form.The change in static pressure, pstat, can be mea-sured or calculated from the measured or estimatedmaximum velocity in individual components usingthe relationship, pstat = 0.5 V

2, here is thewater density and V is the local flow velocity. Thisflow-velocity effect is also called dynamic pressureor velocity head.

Cavitation, thoroughly researched in the 1960sand 1970s, is a damage mechanism well known inthe marine industry and among pump manufactur-ers. In steam power systems, it has been mostly aproblem with valves and boiler feed pumps whichcan be damaged within a few minutes of operationwhen deprived of proper suction head. Such headnormally is provided by the deaerator, typicallylocated more than 30 ft above the pump. Problemsin the 1990s at nuclear units prompted EPRI to

Checklist helps identify FAC, cavitation before theybecome serious problems

Theres little reason for a plant manager to besurprised that his or her plant is experiencingFAC and/or cavitation damage. The majority of

combined-cycle (CC) facilities were designed andbuilt to meet the needs of the competitive genera-tion market. The large number of plants orderedin the 1999-2002 timeframe stretched the person-nel and material resources of the entire industry.Designs and construction work often did not getthe rigorous review and oversight that had becomea tradition in the generation industry. Mistakes weremade.

Also, many asset owners thought CC plantsso simpletypically, just a matter of hooking upmodules on a slab of concrete and connecting gasand electric linesthat the detailed procedures

used for coal-fired and nuclear plants didnt apply.Another mistake, as plant managers know well.One thing for certain, the industry has a wealth

of knowledge of FAC and cavitation as the manyreferences at the end of this article attest. Thisinformation offers a competitive advantage to theplant manger who takes the time to do the appro-priate eavaluations. It helps identify areas whereFAC and cavitation already exist and where they arelikely to occur, what corrective action is warranted,and what type of monitoring program will enableyou to avoid forced outages and the possibility oflife-threatening damage.

Assessment of the propensity of individualsystems and components to FAC and cavitationbegins with a comprehensive plant walkdown pay-ing particular attention of areas of attack identi-

fied in the adjacent text. Your evaluation shouldconsider the combined effects of componentgeometry, flow velocity, water and steam proper-

ties, material composition, water chemistry, andoperating experience.Consider these objectives for your evaluation:Find and select components to be inspected.Interpret NDE results.Identify root causes of wall thinning.Determine inspection interval and safetymargin.Determine effects on cycle iron transport.Recommend engineering solutions.Project tasks to consider include:Preliminary assessment (drawings, flowvelocities, cycle design, experience, leaks).

Component details and actual installation(walkdown, steel composition, history).Final system and/or component descriptionand operating and inspection/maintenancehistory.Water-treatment history and local chemistry.Computer modeling, calculation of erosion/corrosion rates, contributions of individualeffects.Monitor cavitation noises and the rate of wall-thinning.Finally, document your conclusions and recom-

mendations in a formal report for executive review

and implement engineering solutions approved bythe asset owner. Regular follow-up inspections ofsusceptible systems and components are recom-mended.

Changeinstatic

pressure,psi 294

221

147

73.5

00 65.6 131.2 196.8

Flow velocity, ft/sec

Rateofweightloss,mg/hr

70

60

50

40

30

20

10

00 5 10 15 20 25 30 35 40

Test time, hr

Brass

Mild steel

High-tensile brass

Gunmetal

Monel

Stainless steel

10. Relationship betweenflow velocityand thereduction ofstatic pressure can beused to estimate the sus-ceptibility to cavitation (left)

11. Susceptibilitytocavitation of variousmaterials used in pow-erplant systems illus-trates relative resistanceof stainless steel (right)


6/7



include cavitation effects in its computer. UnlikeFAC, which is mostly confined to carbon-steelcomponents, cavitation can attack any material,including stainless steels.

Some piping and other component damage thathad been attributed to FAC actually was caused bycavitationor possibly by an interaction of cavita-tion and FAC, because the flow-velocity and turbu-

lence effects are similar and the surface damageoften looks the same.Any system handling water at near saturation

conditions is susceptible to cavitation damage. Forexample, the l-p section of condensate/feedwatersystems, such as the suction of booster and boilerfeed pumps, can be close to saturation. Saturationconditions can be approached by locally increasingflow velocity around obstacles. Also, by reducing thestatic pressure of the water in turbulent regions, orby increasing water temperature.

Components that have been damaged by cavita-tion include pipes, valves, orifices, pumps, feedwa-

ter-heater drains, and other feedwater and auxil-iary water components. For example: A feedwaterpipe, believed to have been thinned by cavitationafter a quill, ruptured in a paper mill. Feedwaterapproached the saturation conditions because aleaking feedwater heater increased the water tem-perature and the excessive pressure drop causedby various piping-system components between thefeed pump and the drum reduced the static pres-sure.

Management control for preventing cavitationdamage is similar to that for FAC. First, conduct apreliminary evaluation of all cycle systems, making

sure to include an estimate of the component pres-sure in relation to the saturation pressure under allmodes of operation. Next, schedule a walkdown ofall the systems, paying particular attention to thenoises generated by cavitation. Finally, inspect forthinning of selected susceptible components.

Where possible, the actual pressures, tempera-tures, and flow velocities should be measured or oth-erwise determined and used in the cavitation evalu-ation. When susceptible components are identified,consider installing acoustic emission monitoringinstrumentation to track cavitation long-term. Typi-cal areas where cavitation may occur include: HRSGdowncomers, particularly near the lower headersand in economizer-to-drum feedwater pipes; sectionsof pipe after thermowells and similar obstructions;control valves; condensate, booster, and feedwaterpumps; and pump suction pipes.

As a guide to estimating susceptibility to cavita-tion, use Fig 2, which was developed for FAC, andinclude pressure and temperature information. Fig10 presents the relationship between the reductionof static pressure and flow velocity, which also canbe used to estimate susceptibility to cavitation.

Material properties.Unlike FAC, all materialsused in steam-cycle water systems are susceptibleto cavitation damage (Fig 11). The material prop-erty which correlates best with the susceptibilityto cavitation is the fatigue limit. However, it is notclear whether, for various aqueous environments,

the cavitation correlates with air-fatigue or corro-sion-fatigue properties.

Water chemistry probably does not play amajor role in the cavitation damage found in steamcycles. However, effects of concentrated impuri-ties have been measured and have confirmed thata corrosive environment can accelerate cavitation.While cavitation is most often caused by the col-

lapse of steam bubbles, it can also be caused bygases, such as nitrogen and oxygen, and volatilechemicals coming out of solution in water and sub-sequently redissolving.

RecommendationsEvery CC and cogeneration plant should havea formal program for preventing FAC and cavi-tation, starting with an early design review thatconsiders all the parameters influencing FACdescribed in Fig 1.Where organic water-treatment chemicalssuch as amines, dispersants, and oxygen scav-

engersare used, evaluate their effects and theeffects of their decomposition products.When using any FAC software, play special atten-tion to the representation of pH at temperature,pH of water droplets, concentration of the oxygenscavenger, and the concentration of oxygen.Inspect piping downstream of all orifices, ther-mowells, sampling nozzles and chemical injectionquills, and leaking valves. Also check HRSG blow-down lines, downcomers, headers, drum liners,feedwater pipes, saturated steam pipes, steamseparation systems, turbine extraction pipes andextraction valves, feedwater heater drain valves

and shells, feedwater piping, condensers, andboiler-feed-pump recirculation lines.Select a reliable and accurate method for identi-fying wall thinning. Your best options: ultrasonicwall-thickness measurements, x-ray of piping andother components, pulsed eddy-current technique,and the magneto-strictive sensor technique.Finally, remember that cavitation can be detect-

ed on-line by listening to the noise produced bythe collapsing steam or gas bubbles using acousticmicrophones or by acoustic emission instrumenta-tion. It is important to establish critical locations forperiodic long-term monitoring. Continuous in-linemonitoring is an alternative. CCJ

References

Section I: Erosion/corrosion

1. Low-Temperature Corrosion Problems in Fossil Power PlantsState of Knowledge Report, TR-1004924, Electric PowerResearch Institute, December 2003

2. O Jonas and L Machemer, Tight Control of Cycle Chemistry Keyto Successful Commissioning, Combined Cycle Journal, FirstQuarter 2004

3. O Jonas, Safety Issues in Fossil Utility and Industrial Steam Sys-tems, Materials Performance, May 2001. See also http://www.steamcycle.com/safety_issues_pdf.htm

4. O Jonas, Erosion-Corrosion of PWR Feedwater Piping Sur-vey of Experience, Design, Water Chemistry, and Materials,NUREG/CR-5149, ANL-88-23, US Nuclear Regulatory Commis-sion, March 1988

5. G Cragnolino, et al, Review of Erosion-Corrosion in Single-PhaseFlows, NUREG/CR-5156, ANL-88-25, US Nuclear RegulatoryCommission, April 1988

6. S Bush, The Effects of Erosion-Corrosion on Power Plant Piping,


7/7

Proceedings of the 59th General Meeting of the National Boardof Boiler & Pressure Vessel Inspectors, Volume VII, No. 1, May1990

7. Flow-Accelerated Corrosion in Power Plants, TR-106611, Elec-tric Power Research Institute, 1996

8. V K Chexal, et al, Recommendations for an Effective Flow-Accelerated Corrosion Program, NSAC-2021, Electric PowerResearch Institute, November 1993

9. Guidelines for Controlling Flow-Accelerated Corrosion in FossilPlants, TR-108859, Electric Power Research Institute, June1998

Section II: Effects of water chemistry on erosion-corrosion

10. O Jonas, Steam, Chemistry, and Corrosion in the Phase Tran-sition Zone of Steam Turbines, TR-108184, Electric PowerResearch Institute, February 1999

11. O Jonas, Use of Organic Water Treatment Chemicals, VGBConference, Organische Konditionierungs-und Sauerstoffbinde-mittel (Lahnstein, Germany), 1994

12. O Jonas, Controlling Oxygen in Steam Generating Systems,Power, May 1990

13. O Jonas, New Oxygen Scavengers, Jonas Inc, 199014. O Jonas, Reduction of Feedwater Iron by Minimizing Oxygen

Scavengers, Jonas Inc, October 1997

Section III: Inspection methods and codes, erosion-corrosion

15. NDE of Ferritic Piping for Erosion-Corrosion, NP-5410, Elec-tric Power Research Institute, September 1987

16. Assessment of the Pulsed Eddy Current Technique: DetectingFlow-Accelerated Corrosion in Feedwater Piping, RS-109146,Electric Power Research Institute, January 1998

17. Assessment of Magnetostrictive Sensor Technique: DetectingFlow-Accelerated Corrosion in Feedwater Piping (Revision 1),RS-108449-R1, Electric Power Research Institute, February1998

18. O Jonas, Steam Generation in Corrosion Tests and Standards,ASTM MNL 20, June 1995

19. Requirements for Examination of Class 1, 2, and 3 Systems forDetection of Pipe Wall Thinning Due to Single-Phase Flow-Accel-erated Corrosion, ASME Boiler & Pressure Vessel Code (SectionXI, Subsection IWH), to be published

20. Examination Requirements for Pipe Wall Thinning Due toSingle-Phase Erosion and Corrosion, ASME Boiler & Pressure

Vessel Code (Section XI), Case N-480

Section IV: Other references on erosion-corrosion

21. O Jonas, Alert: Erosion-Corrosion of Feedwater and Wet SteamPiping. Power, February 1996. See also www.steamcycle.com/plant_alert.htm

22. O Jonas, Control Erosion-Corrosion of Steels in Wet Steam,Power, March 1985. See also www.steamcycle.com/control_of_erosion_corrosion

23. H G Heitmann and W Kastner, Erosion-Corrosion in Water-Steam CyclesCauses and Countermeasures, VGB Kraftwerk-stechnik 62, March 1982

24. W Kastner, et al, Calculation Code for Erosion-CorrosionInduced Wall Thinning in Piping Systems, Nuclear Engineeringand Design 119, 1990

25. L Goyette and G Zysk, Material Sampling in Erosion-CorrosionPrograms, Codes and Standards in a Global Environment (PVP Vol259),American Society of Mechanical Engineers, 1993

Section V: Cavitation

26. R Knapp, J Daily, and F Hammitt, Cavitation, McGraw Hill

Book Company, New York, 197027. I Pearsall, Cavitation, M&B Monograph ME/10, Mills & Boon,

London, 197228. J Tullis, Choking and Super Cavitating Valves, Journal of

the Hydraulic Division, American Society of Civil Engineers,December 1971

29. C Preece, Cavitation Erosion, Treatise on Materials Science andTechnology (Vol 16),Academic Press Inc, New York, 1979

30. R Mahini, B Chexal, and J Horowitz, Developing PredictiveModels for Cavitation Erosion, Codes and Standards in a GlobalEnvironment (PVP Vol 259), American Society of MechanicalEngineers, 1993

31. A Method to Predict Cavitation and the Extent of Damage inPower Plant Piping, TR-102198 and TR-102198-T2, ElectricPower Research Institute, 1993

32. J P Tullis, Cavitation Guide for Control Valves, NUREG/CR-6031, US Nuclear Regulatory Commission, April 1993

33. Guidelines for Prevention of Cavitation in Centrifugal Feed

Pumps, GS-6398, Electric Power Research Institute, 198934. A Bruthman, Feedwater Heater Design Standards and Prac-

tices, Proceedings of the Feedwater Heater Workshop, ElectricPower Research Institute, July 1979

Panel Discussions of

Special Interest to

HRSG USERSat the upcoming

INTERNATIONAL

WATER

CONFERENCE

Pittsburgh

October 17-21

Current Ideas for Chemistry Control andOperation of HRSGsParticipants include Dave Daniels, IrvCotton, and Luis Carvalho

Pros and Cons of Amine Use inIndustrial and Utility Power Plants

Participants include Mike Rootham, JimBellows, Bill Moore, and Albert Bursik

Other Presentations ofInterest to HRSG Users Monitoring and control in steam

generation cycles New concepts in EDI design Biofouling control in cooling

systems Use of heat-tolerant RO mem-

branes for condensate polishing

LISTEN

LEARN

PARTICIPATE

Complete program at

www.eswp.com/water(click on brochure link)


http://www.eswp.com/waterhttp://www.eswp.com/water

7f issue 3 fac link

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