Progress in Recovery Boiler Progress in Recovery Boiler Deposit Removal StudiesDeposit Removal Studies

Honghi TranPulp & Paper Centre University of TorontoToronto, CANADA

The 7th International Colloquium on Black Liquor Combustion and Gasification Jyväskylä, Finland, July 31 - August 2, 2006

ResearchersResearchersFaculty

Markus BussmannDonald CormackHonghi Tran

Research StaffDr. I.M. Jameel*Dr. Andrei KaliazineDr. Morteza Eslamian

Graduate StudentsMark Martinnez*Secuk Ozcan*Resa Sabet*Kayhan Kermani*Danny Tandra*Babak EmamiAmeya Pophli

Note: * graduated or left

Fouling of Tube SurfacesFouling of Tube SurfacesFouling rate is the difference between the deposit accumulation rate (Ra) and the deposit removal rate (Rr):

Rf = Ra - Rr

Much work has been done on Ra; little has been done on Rr

Factors Affecting Deposit RemovalFactors Affecting Deposit RemovalForce exerted on the deposit the jetDeposit strengthDeposit-Jet interaction

Deposit

Nozzle

Sootblower Jet

Force

Force Exerted on a DepositForce Exerted on a DepositDepends on:

Sootblower Jet Peak impact pressure (PIP)Nozzle design, lance pressure, steam flow rateDistance between nozzle and deposit

Deposit size (thickness), shape, locationJet-deposit interaction

Jet impact angleExposure time

Deposit StrengthDeposit StrengthWhat strength?

Compressive strengthBend strength, orAdhesion strength

Difficult to reproduce the deposit-tube interfacial bond in the laboratory

Fluid Deposit Fluid Deposit -- Jet InteractionJet Interaction

BrittleFluid(Plastic)

Tube

Deposit

Interfacialbond

Jet

Before

T0

BrittleFluid(Plastic)

Tube

Deposit

Interfacialbond

Jet

After

T0

Brittle Deposit Brittle Deposit -- Jet InteractionJet Interaction

Brittle

Tube

Deposit

Interfacialbond

Jet

Before

Brittle

Tube

Interfacialbond

Jet

After

Deposit Removal by Deposit Removal by DebondingDebonding

Jet

Blow from Front(Difficult)

Deposit

Jet

Blow from Behind(Easy)

Deposit

Evidence of Evidence of DebondingDebonding

Deposit Removal Studies Using EFRDeposit Removal Studies Using EFR

Deposit compositionTube surface temperatureDeposit thicknessJet impact angle Gas/particle velocityParticle sizeSO2

1.81.61.4

1.00.80.60.40.20.0

1.2

2 10 12 14 164 6 8mole% Cl/(Na+K)

Min

imum

PIP

(MPa

)

Probe temp.=400oC0% K% CO3

Effect of Chloride on RemovalEffect of Chloride on Removal

0 mole% K/(Na+K)

5 mole%

10 mole%

20 mole%

Effect of Potassium on Deposit RemovalEffect of Potassium on Deposit Removal(5 mole% Cl/(Na+K), no CO(5 mole% Cl/(Na+K), no CO33))

Effect of SOEffect of SO22 on Removal on Removal

0.0

0.2

0.4

0.6

0.8

1.0

0 200 400 600 800 1000 1200

SO2 Conc., ppm

PIP,

MPa

600-710μ

425-600μ

300-425μ150–300μ

Correlation between PIP & SulphateCorrelation between PIP & Sulphate

0.0

0.2

0.4

0.6

0.8

1.0

20 30 40 50 60 70 80Mole% SO4/(Na2+K2)

PIP

, MP

a

600-710um

425-600um

300-425um

150-300um

Effect of Sulphate Content on Effect of Sulphate Content on TTStkStkEFR Tests, Black Liquor Particles + SO2

650

700

750

800

850

Stic

ky T

empe

ratu

re, o C

BL+SO2

650

700

750

800

850

0 20 40 60 80 1000 20 40 60 80 100mole% SO4/(Na2+K2)mole% SO4/(Na2+K2)

2

Effect of Thermal SinteringEffect of Thermal Sintering

10 20 30 40 50 600.0

0.1

0.2

0.3

0.4

0.5

0

PIP,

MPa

0.0

0.1

0.2

0.3

0.4

0.5

0 10 20 30 40 50 60Exposure Time, min.

No SO2

350 ppm SO2350 ppm SO2

ImplicationsImplicationsHigh SO2 makes deposits easier to remove, due probably to an increase in particle sticky temperatureIn a high (350 ppm) SO2 atmosphere, sulphation of carbonate reduces deposit strength with time

Effects of Probe Temperature & Effects of Probe Temperature & ClClM

inim

um P

IP (M

Pa)

1.41.2

0.8

0.60.40.2

0.0

1.0

200 300 400 500 600Probe Temperature (oC)

5 mole%Cl/(Na+K)

10 mole%Cl/(Na+K)

Economizer160-270oC: LOW

Superheater300-500oC: HIGH

Generating Bank270-300oC: MEDIUM

Tube Temperature & PIP Requirement

JetJet--DepositDeposit--Tube InteractionTube InteractionAnalysis of Sootblowing VideosCFD Modeling and Laboratory StudiesFocus on both PIP and force

DistanceJet angleOff-set

Jet Deposit

Tube

Effect of OffsetPlaten

Offset = 1.9 cm

5 cm

NozzleProbe

Jet

Platen

0

20

40

60

80

100

0 10 20 30 40X, cm

PIP

, psi

g

Predicted by CFDLib-SJT model

Experimental Data-This study

X

X/D

Platen

Offset = 1.9 cm

5 cm

NozzleProbe

Jet

Platen

0

20

40

60

80

100

0 10 20 30 40X, cm

PIP

, psi

g

Predicted by CFDLib-SJT model

Experimental Data-This study

X

Platen

Offset = 1.9 cm

5 cm

NozzleProbe

Jet

Platen

0

20

40

60

80

100

0 10 20 30 40X, cm

PIP

, psi

g

Predicted by CFDLib-SJT model

Experimental Data-This study

0

20

40

60

80

100

0 10 20 30 40X, cm

PIP

, psi

g

Predicted by CFDLib-SJT model

Experimental Data-This study

X

X/D

0.45 cm

0

20

40

60

80

100

120

0 5 10 15 20X, cm

PIP

, psi

gExperimental Data-This study

Platen

5 cm

Probe

Platen

Nozzle

Jet

X

Predicted by CFDLib-SJT model

X/D

0.45 cm0.45 cm

0

20

40

60

80

100

120

0 5 10 15 20X, cm

PIP

, psi

gExperimental Data-This study

Platen

5 cm

Probe

Platen

Nozzle

Jet

0

20

40

60

80

100

120

0 5 10 15 20X, cm

PIP

, psi

gExperimental Data-This study

0

20

40

60

80

100

120

0 5 10 15 20X, cm

PIP

, psi

gExperimental Data-This study

0

20

40

60

80

100

120

0 5 10 15 20X, cm

PIP

, psi

gExperimental Data-This study

Platen

5 cm

Probe

Platen

Nozzle

Jet

Nozzle

Jet

X

Predicted by CFDLib-SJT model

X/D

Effect of Blowing Angle

Sootblower

Xδ

R

Platen

Sootblower

-90 -60 30- 0 30 60 90

Blowing Angle δ

V (inch/s)R (inch)

40

80

120

160160

00

V

Jet between Plates: Velocity Contour

Model Deposit Removal By Air JetModel Deposit Removal By Air JetPlaster of Paris : Water = 1:1

Alstom PowerAracruz CeluloseBabcock & WilcoxBoise Paper SolutionsBowater CanadaCenibraClyde-BergemannDaishowa-MarubeniDiamond Power International

DomtarGeorgia PacificInternational PaperIrving Pulp & PaperKvaerner PulpingMeadWestvacoStora-Enso ResearchTembecVotorantim Celulose E Papel

NSERC

AcknowledgementsAcknowledgementsMembers of the Research Consortium on

Increasing Energy and Chemical Recovery in the Kraft Process