Solving Power Plant Condenser Tube Problems with Thin Film

Curran International Curran International --www.curranintl.com www.curranintl.com -- Indian Indian Power Stations 13/2//08Power Stations 13/2//08

Solving Power Plant Condenser Tube Problems with Solving Power Plant Condenser Tube Problems with Thin Film Conductive Coating ApplicationsThin Film Conductive Coating Applications

••Evolution of tube ID coating applicationsEvolution of tube ID coating applications

••Improvements in equipment and techniquesImprovements in equipment and techniques

••Thin film materials Thin film materials –– product enhancements product enhancements

••InIn--situ application case historiessitu application case histories


Evolving the maintenance model for tubulars Evolving the maintenance model for tubulars

••Precipitate/particulate fouling and scale, impact operationPrecipitate/particulate fouling and scale, impact operation

••Turbine backpressure, reduced HTR, increased energy costTurbine backpressure, reduced HTR, increased energy cost

••Severe pitting, Severe pitting, ““discoverydiscovery”” NDE may impact T/ANDE may impact T/A

••Collaboration to develop alternative options to reCollaboration to develop alternative options to re--tubetube

••Inhibit corrosion, reduce maintenance, improve reliabilityInhibit corrosion, reduce maintenance, improve reliability


Background of tube ID coatingBackground of tube ID coating

•• Use of shop applied thin film phenolics Use of shop applied thin film phenolics -- 1950s1950s

•• Italian field trials using dispersion Italian field trials using dispersion system system -- 19801980’’ss

•• EPRI/FPC TREPRI/FPC TR--107068 initiated 107068 initiated evaluation in 1990evaluation in 1990

•• Retubed 1987, through wall 1989Retubed 1987, through wall 1989


EPRIEPRI--FPC observationsFPC observations

•• Tube coating v. retube est. $8M (1989)Tube coating v. retube est. $8M (1989)

•• Demonstration project funded 1993:Demonstration project funded 1993:Tube ID surface prep Tube ID surface prep –– achieve NACE 1achieve NACE 1Materials Materials –– ambient cured epoxy phenolicambient cured epoxy phenolic

•• Observations:Observations:Proven resistance to Proven resistance to ““TaprogeeTaprogee”” serviceserviceNDE inspection 1997 NDE inspection 1997 –– corrosion rate lowercorrosion rate lowerSustained long term HT performanceSustained long term HT performanceNo penalty to condenser backpressureNo penalty to condenser backpressure


Equipment development Equipment development –– tube cleaningtube cleaning

•• Standard nozzles inefficient for condenser tube ID cleaningStandard nozzles inefficient for condenser tube ID cleaning

•• University collaboration led to enhanced nozzle designUniversity collaboration led to enhanced nozzle design

•• High kinetic energy, more efficient cleaning High kinetic energy, more efficient cleaning –– Mach II blastMach II blast


““UsedUsed”” exchanger tubes exchanger tubes –– cleaned of magnetite scalecleaned of magnetite scale


•• Airless equipment development Airless equipment development –– filtering, uniform deposition filtering, uniform deposition

•• Fixed or Fixed or ““flexflex”” lance systems, 2/meters/second spray ratelance systems, 2/meters/second spray rate

•• Uniform deposition Uniform deposition –– (+/(+/--) 25 microns ) 25 microns -- .001.001””

Application development Application development –– tube ID coating methodtube ID coating method

Enhanced tube with single coat of epoxy


Tubular coating materialsTubular coating materials

Coating MaterialCoating Material % Solids% Solids Temperature limits Temperature limits –– water/steamwater/steam CatalystCatalyst

Epoxy PhenolicEpoxy Phenolic 67%67% 135 C 135 C –– coating side exposurecoating side exposure Amine curedAmine cured

Novolac epoxyNovolac epoxy 100%100% 135C 135C –– coating side exposurecoating side exposure Amine curedAmine cured

Baked phenolicsBaked phenolics 65%65% 150C 150C –– coating side exposurecoating side exposure Heat cured Heat cured –– 200C200C

ThermoplasticsThermoplastics 100%100% 250C in low pH, 150C in acidic brine250C in low pH, 150C in acidic brine Heat cured Heat cured –– 250C250C

Bisphenol ABisphenol A 100%100% 80C 80C –– coating side exposurecoating side exposure Amine curedAmine cured


Engineered polymersEngineered polymers

•• 70% of total HTR is tube ID boundary layer drag70% of total HTR is tube ID boundary layer drag

•• Coating reduces surface tension 30X Coating reduces surface tension 30X –– elimination of scaleelimination of scale

•• Sustains Sustains ““as newas new”” flow rate; maintains flow profile at tube wallflow rate; maintains flow profile at tube wall

•• 80% improvement compared to uncoated tubes80% improvement compared to uncoated tubes

•• Dialectic barrier between CW and tube wall oxidesDialectic barrier between CW and tube wall oxides


Resistance to heat transferResistance to heat transfer

(T(T00) Steam side water film ) Steam side water film -- 18%18%

(T(T11) Steam side fouling ) Steam side fouling –– 8%8%

(T(T22) Tube Wall ) Tube Wall –– 2%2%

(T(T33) Water side fouling ) Water side fouling –– 33%33%

(T(T44) Water side film ) Water side film –– 39%39%

Advanced Polymers: Lustenador & StaubAdvanced Polymers: Lustenador & Staub


Improving heat transfer performanceImproving heat transfer performance

Coating materialCoating material BTU/hrBTU/hr--ft2 ft2 -- FF

1993 application 1993 application –– 22--3 mils epoxy 3 mils epoxy 0.2850.285

2006 2006 –– University of StellenboschUniversity of Stellenbosch3 mils phenol epoxy 3 mils phenol epoxy –– solvented coating solvented coating

0.3580.358

2006 2006 –– University of StellenboschUniversity of Stellenbosch3 mils phenol epoxy w/conductive pigments3 mils phenol epoxy w/conductive pigments

0.6670.667


•• Eskom Power, South Africa Eskom Power, South Africa –– Corroded tubes; restart Corroded tubes; restart ““mothballedmothballed”” plantsplants

•• China Light and Power/Alstom China Light and Power/Alstom –– Corroded condenser tubes. Corroded condenser tubes.

•• Cottonwood Power, Texas Cottonwood Power, Texas –– Maganese pitting; coated 30% of Unit 1 Maganese pitting; coated 30% of Unit 1

•• Huntley, New Zealand Huntley, New Zealand –– Partial condenser, recovery of corroded tubes.Partial condenser, recovery of corroded tubes.

•• Contact Energy, New Zealand Contact Energy, New Zealand –– Partial condenser, corroded tubes. Partial condenser, corroded tubes.

•• Madsen Navigation Madsen Navigation –– Steam ships, recover corroded tubes Steam ships, recover corroded tubes

•• Valero, Aruba Valero, Aruba –– Condensers, coating of full length tube IDs, tubesheets Condensers, coating of full length tube IDs, tubesheets

•• Reliant Avon Lake, Ohio Reliant Avon Lake, Ohio –– Inhibit corrosion of cooling water tubes Inhibit corrosion of cooling water tubes

•• CP&L, North Carolina CP&L, North Carolina –– Tube ID coating to reduce Cu ion discharge Tube ID coating to reduce Cu ion discharge

•• TVA TVA –– Repair and inhibit erosion of Cu/Ni tubes in 3/mps flow. Repair and inhibit erosion of Cu/Ni tubes in 3/mps flow.

•• Hawaiian Electric Hawaiian Electric –– Hydrogen embrittlement, overexpansion of tube endsHydrogen embrittlement, overexpansion of tube ends

Reference work, application case historyReference work, application case history


Aruba tubesheet and tube IDs, after 8 years salt water service


Cottonwood Energy, Texas – 20 gauge SS tubes, manganese attack; coating material wicks/wets in deeply corroded pit


CLP/Alstom: Single coat (magnified 20X) from CLP; tube IDs CLP/Alstom: Single coat (magnified 20X) from CLP; tube IDs were coated inwere coated in--situ to remediate corrosion. Thin film epoxy situ to remediate corrosion. Thin film epoxy encapsulates pits with protective film.encapsulates pits with protective film.


CP&L – tube ID coating - 5 years service


Cross section of coating exchanger tube, (50X) coatingfills corrosion attack at the weld seam. Pull tests of tubespulled post coating measured >800 PSI adhesive strength.


Coated tube ID – 7 years of cooling water service


Tube ID coating applicationsTube ID coating applications

•• Changing the equation of tubular equipment maintenanceChanging the equation of tubular equipment maintenance

•• Effective cost/short duration v. traditional tube replacementEffective cost/short duration v. traditional tube replacement

•• Proven performance >45 power plants since 1995Proven performance >45 power plants since 1995


Edward Curran, CEOEdward Curran, CEO

[email protected]@curranintl.com

www.curranintl.comwww.curranintl.com

Booth #530Booth #530

mailto:[email protected]

http://www.curranintl.com/

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Solving Power Plant Condenser Tube Problems with Thin Film