Results from Initial Material Exposure Tests in OxyFuel Environment

1st OXYFUEL COMBUSTION CONFERENCE

Date: 8th -11th September 2009Radisson Hotel, Cottbus, Germany

Anders HjörnhedeMelanie MontgomeryMartin BjurmanAlexander GerhardtAlexander GerhardtNicklas Folkesson (Chalmers University)

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Need for Corrosion and Material testing in OxyFuel environments?g y

Corrosion rate: “Same as in lignite fired boilers” ?

CO2 N2

Carburisation Influence the heat transfer from flue gas to heat absorbing surfaces

Risk of enrichment of corrosive species (recirculation)Risk of enrichment of corrosive species (recirculation)More corrosive flue gas and condensates will formBoth oxyfuel- and air fired modes must be handled

Higher efficiency super austenitic steels, Ni-based materials

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Corrosion tests in OxyFuel environments (Vattenfall)y ( )High temperature corrosion tests (Superheater)

IVD KSVA-rig, StuttgartCooled samples, <40hrs, 0,5 MW burner rig

Chalmers, GothenburgIso-thermal samples, 670hrs, furnace, synthetic mix

CEBRA-rig BTU, JänschwaldeCooled samples, <300hrs, 0,5 MW burner rig

OxPP, Schwarze PumpeCooled samples, <250hrs (2000hrs), 30 MW OxyFuel Pilot Plant

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Cooled samples, 250hrs (2000hrs), 30 MW OxyFuel Pilot Plant

IVD: corrosion rateMass Increase

3,0

Lausitz: Air (reference) F-G: 950°C

e [g

/x h

rs]

2,0

2,5Lausitz: Air (reference), F G: 950 CLausitz: Oxy - Fuel, test 1, F-G: >1050°CKleinkopje: Oxy - Fuel, F-G: 1050°CLausitz: Oxy - Fuel, test 2, F-G: 950°C

ass

Cha

nge

1 0

1,5

orm

alis

ed M

0,5

1,0

15Mo3 13CrMo44HCM 12ASuper 304 Kanthal Alloy 800Sanicro 28Sanicro 63 C-2000 Inconel 625 Nimonic 26360 HT R

No

-0,5

0,0

NiCrAl

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Material

IVD: OxyFuel HardCoaly

Alloy 625Alloy 625Ni-based super alloy

Exposure time: 26 hrs Mtrl temp: 630°CMtrl temp: 630 CF-G temp: 1050°C

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Chalmers: Air XRD-analysisy

NiCrAlNiCrAl

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Chalmers: XRD OxyFuely

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CEBRA: Sanicro 28, super austenitic steel, p

Oxyfuel

lignite

287 hrs

570°C

1000°C

Thin, protective oxide

(Indication of ) carburisation

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CEBRA: Hastelloy C-2000 Ni-based alloyy y

Oxyfuel

lignite

287 hrs

570°C

1000°C

CarburisationCarburisation

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CEBRA: Kanthal APMT (FeCrAl)( )

287 hrs

570°CProtective alumina (aluminiumoxide) scale formed

570 C

1000°CNo carburisation

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OxPP: OxyFuel: 15Mo3 “Pre-tests”y

Metal temp: 580°C

Fl t 770°CFlue gas temp: 770°C

Exposure time: c:a 220hrs

Air-mode: 15Mo3 slightly corroded

S in corrosion front

Air mode: 15Mo3 slightly corroded Other materials unaffected

Oxyfuel-mode: 15Mo3 more corroded. Other materials affected

Spectrum C O S Mn Fe

1 33.60 1.30 63.542 24.09 31.52 8.24 20.083 2 69 24 67 3 67 0 35 64 96

Other materials affected

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3 2.69 24.67 3.67 0.35 64.964 2.70 25.13 0.76 71.41

OxPP: OxyFuel Sanicro 63 (Alloy 625) pretesty ( y ) p

Metal temp: 580°C

Fl t 770°CFlue gas temp: 770°C

Exposure time: c:a 220hrs

S in corrosion front

NiO?

Spectrum O S Cr Fe Ni Nb Mo

1 10.79 2.15 0.68 7.87 3.223 28.44 5.08 0.30 5.67 2.855 14.83 2.75 2.37 6.07 15.886 8.24 4.73 6.30 10.88 34.607 12.47 6.23 7.14 4.41 34.758 12.46 9.58 6.42 1.83 36.519 12.00 7.51 26.61 0.95 47.07

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10 21.69 0.76 66.34 3.17 8.0413 22.41 0.76 63.94 3.37 9.51

OxPP: OxyFuel: Sanicro 63: pretesty p

Metal temp: 580°C

Fl t 770°CFlue gas temp: 770°C

Exposure time: c:a 220hrsS in corrosion front

Spectrum C O S Cr Fe Ni Nb Mo

S in corrosion frontNiO?Carburisation

Spectrum 4 22.69 14.52 40.17 16.89 4.42Spectrum 5 2.76 21.63 7.86 0.29 3.45 59.92Spectrum 6 26.42 23.57 11.09 14.81 9.57Spectrum 7 5.46 48.27 13.26 6.85 10.44Spectrum 8 8.33 36.46 13.15 0.54 11.62 14.03pSpectrum 9 15.48 33.66 2.36 5.41 2.72 38.54Spectrum 10 5.68 18.63 13.20 35.40 21.34 4.16Spectrum 11 5.83 26.69 10.97 41.42 0.74 7.46 5.33Spectrum 12 3.74 22.37 32.01 0.77 11.84 5.55 23.02Spectrum 13 4 32 22 27 0 77 61 00 2 95 8 69

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Spectrum 13 4.32 22.27 0.77 61.00 2.95 8.69Spectrum 16 3.55 22.46 0.63 62.09 3.12 8.15

OxPP: 15Mo3, 70 – 170°C, ~10 days pretest, , y p

Air OxyfuelLocated between Eco

Even 316L was more affected from OxyFuel-firing

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OxPP: Corrosion test 1: 2000hrs

Probe no.Metal temp.

Exposed sinceLevel

1. On-line corrosion sensor 580 Furnace 2nd 090312-Out 82. Conventional HT corrosion probe 580 Furnace 2nd 2009-06-03 17:00 83. Conventional HT corrosion probe 650 Furnace 2nd 2009-06-03 17:00 74. Conventional HT corrosion probe 650 Furnace 2nd 2009-06-11 15:00 7p5. Gradient corrosion probe 170-70 Furnace 3rd 2009-06-03 17:00 126. Gradient corrosion probe 170-70 Furnace 3rd 2009-06-03 17:00 137. Water wall corrosion probe 430 Furnace 1st 2009-05-19 5

580 Intermittent

8. Deposit measurement probe

580, 650,

760ºC Furnace 2nd

Intermittent

8

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Summaryy• Strong indication of higher material wastage rate in OxyFuel

• Increased S-concentration in corrosion front• Ni-based alloys may form non-protective NiO• Carburisation (super austenitic steels, Ni-based)Carburisation (super austenitic steels, Ni based)• (Cu – containing alloys may form non-protective Cu-crystallites)

Al containing materials ma form protecti e o ide (Al O )• Al-containing materials may form protective oxide (Al2O3)and is not getting carburised

• Super austenitic stainless steels (30%Fe, 30%Ni, 30%Cr) forms protective oxide

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Chalmers: 304HCu OxyfuelChalmers: 304HCu, Oxyfuel

Alloy specially developed for use in USC-boilers

Cu oxide

Some deposit removed before analysis

Cu rich oxide crystallites found on a few samples.

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Corrosion probe: IVD, BTU and OxPPp ,

500 kW RigInternally cooled test probe

Simulates superheater alloysp y

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Chalmers: Iso-thermal tests in furnace

Temperature: 630°CAtmosphere: 2% O

Temperature: 630°CAtmosphere: 4 7% O

Oxyfuel Air

Atmosphere: 2% O2 vol%

59% CO2

38,75% H2O0 25% SO

Atmosphere: 4,7% O2

72,3% N2

13,7% CO2

8 35% H O0,25% SO2

Gas velocity: 200 ml/minExposure time: 672 hMaterial: Sanicro 63 (cleaned lignite

8,35% H2O0,07% SO2

Gas velocity: 200 ml/minExposure time: 672 hMaterial: Sanicro 63 (cleaned, lignite,

bituminous coal)Alloy 800 (cleaned, lignite,bituminous coal)

Exposure time: 672 hMaterial: HCM12A (lignite)

X20 (polished)Alloy 800 (cleaned lignite)bituminous coal)

Super 304 (cleaned, lignite)304L (polished)

Alloy 800 (cleaned, lignite)60HT (lignite)APMT (polished, lignite)Inconel 625 (lignite)

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( g )304L (polished)

IVD: Test conditions: ligniteg

Test 1 Test 4 Test 3

Fuel Lausitz lignite coal Lausitz lignite coal Lausitz lignite coalFuel Lausitz lignite coal Lausitz lignite coal Lausitz lignite coal

Case OxyFuel 29% OxyFuel 29% Air (21%)

Stoichiometry λ 1.12

O2dry excess 2,8 vol% 5,5 vol% 4,0 vol%

Water content 17,9 vol%

CO2 92.0 vol% 88,2 vol% 16,6 vol%2 , ,

NOx 442 ppm 318 ppm 452 ppm

SO2 1308 ppm 1717 ppm 718 ppm

Exposure time 38 hrs 33 h 33 h

Metal temp. 630°C 630°C 630°C

Flue gas temp. 900°C 1050°C 950°C

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