corrosion in black liquor pyrolysis and combustion gas ... · h2 12.04 6.67 5.16 o2 0.27 0.52 0.55...

1

Corrosion in Black Liquor Pyrolysis and Combustion Gas Environments

Preet M. SinghInstitute of Paper Science and Technology

Atlanta, Georgia

Colloquium on BL Combustion and GasificationPark City, UtahMay 13th, 2003

Recovery Boiler

To stackElectrostaticprecipitator

Primary

Secondary

TertiaryAir delivery:

Black liquor

Smelt

Economizer

BoilerSuperheater

Screen Tubes

2

Differences in Fireside Tube Surface Corrosion

“Corrosive” Area“Non-Corrosive” Area

Thermocouples and Gas-line for Environment Sampling

Filters for Gas-line

3

Instrumentation for Boiler Environment Characterization

0

5

10

15

20

25

30

1 foot 1 inch Waterwall surface

% i

n D

ry G

ases

High Corrosion Area Low Corrosion Area

Hydrogen Sulfide in RB

4

0

0.1

0.2

0.3

0.4

0.5

0.6

1 foot 1 inch Waterwall surface

% i

n D

ry G

ases

High Corrosion Area Low Corrosion Area

Methyl Mercaptan in RB

Average Gas Composition at Waterwall Surface - Boiler #1

Gas Species High Corr. Area Low Corr. Area

N2 24.8 % 38.6 %CO2 18.8 % 13.4 %CO 11.7 % 9.2 %H2 2.4 % 1.4 %O2 2.9 % 4.4 %

CH4 4.0 % 0.8 %H2S 18 % 3.8 %

SO2/COS 0.2 % 0.18 %Meth. Mercaptan 0.17 % 0.02 %

65% Solids-Black liquor is sprayed on side-walls

5

Black Liquor “Pyrolysis” on Waterwall Tubes - High Local Concentrations of Sulfur Bearing Gases

High Corrosion Of Waterwall Due to Black Liquor Spray in Boiler #1

Recovery Boiler #2

6

Locations of Cut-line Corrosion in a BoilerMid-Furnace Corrosion

Composite Tubes

High Corrosion Areas

Rear Wall

Front WallRight Wall

(South)Left Wall(North)

C-Steel Tubes

Primary Airports

Secondary Airports

Auxiliary Burners

Liquor Guns

Locations of Mid-Furnace Corrosion Boiler #4

Gas Sampling PortComposite Tubes

(High Corrosion Rate)

Front Wall

Rear Wall

Left Wall

1

113 1 115 1

113 115RLM

RLT

RCM 34’

RCT 41’

LB 25’

LF 25’

RLBRCB 27’

7

Gases at Waterwall SurfaceMid Furnace - Boiler #5 (North Wall)

65 - 68% Solids-Black liquor

Gas Species % in HighCorr. Area

% in LowCorr. Area

% 12' AboveHigh Corr

N2 10.60 40.62 46.74CO2 14.23 17.71 17.87CO 27.95 13.57 13.98H2 12.04 6.67 5.16O2 0.27 0.52 0.55

CH4 4.42 1.82 1.59H2S 0.91 0.81 0.86

SO2/COS 0.20 0.10 0.12CH3SH 0.030 0.023 .013(CH3)2S 0.033 0.028 0.033

CS2 0.0012 0.0018 0.0024(CH3)2S2 0.0019 0.0012 0.0009

When black liquor is sprayed or ends-up intentionally or unintentionally on waterwalls

local pyrolysis of black liquor on waterwall surface

Higher concentrations of sulfur bearing gases locally

higher sulfidation or corrosion of carbon steel waterwalls in these areas

Corrosion in Lower Furnace

8

Corrosion Kinetics

Thermobalance for RB Simulation Tests

DifferentGasesMass Flow Meters

and Controllers

Gas outlet

Furnace

Thermocouple

Gas inlet

CathetometerQuartz spring

Test Coupon

Platinum wire

EndcapPyrex tube

9

Effect of Temperature

C-Steel, SA-210 at 320oC and 400°C in High Corrosion Gases From RB#1

C-Steel, SA-210 @ 320 and 400°C in High-RB#1 Gases

0

10

20

30

40

50

60

0 4 8 12 16Time, days

Wt.

Gai

n, m

g/cm

² High - RB#1-400CHigh - RB#1-320C

10

SA210 in HC Gases at 320oC


100.00

0.0

95.89

4.11

Spot #1

100.00

0.00

97.92

2.08

Spot #3 Spot #6

100.00Total

14.89O

74.54Fe

10.57S

At%Element

11



O

Fe

S

Element

0.00

94.6

1.55

Spot #1

0.00

48.24

49.53

Spot #2

0.00

46.72

51.94

Spot #5 Spot #10

25.12

68.02

6.86

At%

12

Effect of Temperature on Corrosion Rate of 304 SS in Gases Containing Only H2S and H2

Source – IPST Corrosivity Database

304SS in H2S + H2 Gas Mixtures (Partial Pressure of O2 = 0.0)

0.1

1

10

100

1000

200 300 400 500 600 700Temperature (oC)

Cor

rosio

n R

ate

(mpy

)

Effect of Gas Composition

13

Lower Furnace Gas Compositions Used in Laboratory Tests

87.20.000.000.020.361.180.000.000.00.012.0High Corrosivity w/o O2 (HC)

43.60.000.000.000.230.5421.800.1010.119.74.0Low Sulfur (LS)

70.50.000.000.052.045.990.000.006.10.014.7High Sulfur (HS)

N2CS2CH32SCH3SHCOSH2SCOCH4O2CO2H2

1.00E-362.17E-143.60E-344.32E-11High Corrosivity w/o O2 (HC)

3.33E-362.97E-133.92E-291.68E-10Low Sulfur (LS)

6.12E-033.59E-136.12E-037.14E-10High Sulfur (HS)

PO2PS2PO2PS2

320oC480oCLower Furnace Recovery Boiler Gases

(HS) High Sulfur Containing RB Gases

0.2

12.1

1.40.1

1.7 0.90

5

10

15

20

25

30

35

40

304-L SA210 I-625 304-L SA210 I-625

Alloy

Cor

rosi

on R

ate

(mpy

)

HS-Gases at 480 oC HS-Gases at 320 oC

14

(LS) Lower Sulfur Containing RB Gases

0.68

16.89

1.99 0.96 0.84 1.100

5

10

15

20

25

30

35

40

304-L SA210 I-625 304-L SA210 I-625

Alloy

Cor

rosi

on R

ate

(mpy

)

LS-Gases at 480 oC LS-Gases at 320 oC

(HC) Low Oxygen Containing RB Gases

9.5

36.4

13.8

1.1

29.3

1.5

0

5

10

15

20

25

30

35

40

304-L SA210 I-625 304-L SA210 I-625

Alloy

Cor

rosi

on R

ate

(mpy

)

HC-Gases at 480 oC

HC-Gases at 320 oC

15

Effect of Sulfur Partial Pressure on Corrosion Rate of 304 SS in Gases Containing Only H2S and H2 at 400oC

Corrosion Rate of 304 SS at 400oC as a function of Sulfur Partial Pressure in (H2S + H2) Gas Mixtures

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

1.0E-15 1.0E-13 1.0E-11 1.0E-09 1.0E-07 1.0E-05 1.0E-03

Partial Pressure of Sulfur (atm.)

Cor

rosi

on R

ate

(mpy

Source – IPST Corrosivity Database

Phase Stability Diagrams for Fe, Ni, and Cr in Presence of O2 and S2 at 320oC

1.00E-362.17E-14High Corrosivity w/o O2 (HC)

3.33E-362.97E-13Low Sulfur (LS)

6.12E-033.59E-13High Sulfur (HS)

PO2PS2

320oCLower Furnace

Recovery Boiler Gases

0-5-10-15-20-25-30-35-40

0

-5

-10

-15

-20

-25

-30

-35

-40

log pS2(g)

log pO2(g)Constant value:T / °C = 320.00

Predominance Diagram for Ni-O-S System

Ni(FCC)Ni(FCC)NiONiO

NiS(A)NiS(A)

NiS2NiS2

Ni3S2Ni3S2NiSO4NiSO4

0-5-10-15-20-25-30-35-40

0

-5

-10

-15

-20

-25

-30

-35

-40

log pS2(g)


Predominance Diagram for Cr-O-S System

Cr2O3Cr2O3

Cr2S3Cr2S3

Cr2(SO4)3Cr2(SO4)3

0-5-10-15-20-25-30-35-40

0

-5

-10

-15

-20

-25

-30

-35

-40

log pS2(g)


Predominance Diagram for Fe-O-S System

Fe2O3Fe2O3Fe3O4Fe3O4

FeSFeS

FeS2FeS2

Fe2S3Fe2S3

FeSO4FeSO4

Fe2(SO4)3Fe2(SO4)3

16

Phase Stability Diagrams for Fe, Ni, and Cr in Presence of O2 and S2 at 480oC

3.60E-344.32E-11High Corrosivity w/o O2 (HC)

3.92E-291.68E-10Low Sulfur (LS)

6.12E-037.14E-10High Sulfur (HS)

PO2PS2

480oCLower Furnace

Recovery Boiler Gases

0-5-10-15-20-25-30-35-40

0

-5

-10

-15

-20

-25

-30

-35

-40

log pS2(g)


Predominance Diagram for Ni-O-S System

Ni(FCC)Ni(FCC) NiONiO

NiS0.84NiS0.84NiS(A)NiS(A)

NiS2NiS2

Ni3S2Ni3S2

NiSO4NiSO4

0-5-10-15-20-25-30-35-40

0

-5

-10

-15

-20

-25

-30

-35

-40

log pS2(g)


Predominance Diagram for Cr-O-S System

Cr2O3Cr2O3

CrS1.17CrS1.17

Cr2S3Cr2S3

Cr2(SO4)3Cr2(SO4)3

0-5-10-15-20-25-30-35-40

0

-5

-10

-15

-20

-25

-30

-35

-40

log pS2(g)


Predominance Diagram for Fe-O-S System

Fe(A)Fe(A) Fe2O3Fe2O3

Fe3O4Fe3O4

Fe0.877SFe0.877S

FeSFeS

FeS2FeS2

Fe2S3Fe2S3

FeSO4FeSO4

Fe2(SO4)3Fe2(SO4)3

What About Gasifiers?

17

Low Temperature Gasifier Environment

27.5481H2O (v)Water vapor

15.2311CO2Carbon dioxide

9.9051COCarbon monoxide

44.6459H2Hydrogen sulfide

0.0008(CH3)2S2Dimethyl disulfide

0.0012(CH3)2SDimethyl sulfide

0.0122CH3SHMethyl Mercaptan

1.4789H2SHydrogen sulfide

0.0395C3H6Propane

0.0987C2H4Propene

0.0526C2H6Ethane

0.9862CH4Methane

% Wet basis

Chemical formulaGas Component

7-day results

7-day Weight gain vs. alloy

0

20

40

60

80

100

120

304 304b 310 7-mo 601I 50Cr-50Fe

alloy

wei

ght g

aine

d (m

g/cm

^2)

18

AcknowledgmentsDr. Safaa Al-Hassan

Jorge Perdomo

Jamshad Mahmood,

Tony Clandra

DOE - (DE-FC36-95GO10092)

AF&PA

ORNL - 85X-SY627V

Mill Personnel

IPST Member Companies

corrosion in black liquor pyrolysis and combustion gas ... · h2 12.04 6.67 5.16 o2 0.27 0.52 0.55...

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