coal ash behavior in reducing environments...

Coal Ash Behavior in Reducing Environments Coal Ash Behavior in Reducing Environments (CABRE) III(CABRE) III

Freiberg ConferenceFreiberg ConferenceMay 21May 21––24, 201224, 2012

Josh Stanislowski, Kevin Galbreath, Don McCollor, Josh Stanislowski, Kevin Galbreath, Don McCollor, Bruce Dockter, Scott Tolbert, Jason Laumb, Bob Jensen, Bruce Dockter, Scott Tolbert, Jason Laumb, Bob Jensen, Tyler Curran, Tyler Curran,

d D i l S h it lld D i l S h it lland Daniel Schwitallaand Daniel Schwitalla

© 2012 University of North Dakota Energy & Environmental Research Center.

CABRE III Goal

• Create an advanced model for the prediction of slag and p gash behavior in gasification systems.

• Utilize EERC small pilot-scale gasifiers for the d l t f th d tdevelopment of the data.

• Distribute the model in the form of stand-alone software program.program.

• Pave the way for SABRE IV (Slag and Ash Behavior in Reducing Environments).

EERC . . . The International Center for Applied Energy Technology

Sponsors


Work Plan

• Task 1 ‒ Feedstock Characterization—Completedp• Task 2 ‒ Laboratory Evaluation of Ash Behavior—

Completed• Task 3 ‒ Evaluation of Ash Behavior in Bench- and Pilot-

Scale Systems—Completed• Task 4 ‒ Ash Impacts on Gas Cleanup and CO• Task 4 ‒ Ash Impacts on Gas Cleanup and CO2

Capture—Completed• Task 5 ‒ Modeling of Ash Behavior—Completed• Task 6 ‒ Model Verification—Ongoing• Task 7 ‒ Reporting—Ongoing


Summary of CABRE III Program Status

• Characterization of the sponsor fuels is complete.– Center ligniteg– Falkirk lignite– Illinois No. 6– Petroleum coke

• Each fuel has been tested in the entrained-flow gasifier (EFG).• Falkirk lignite has been tested in the fluid-bed gasifier (FBG).• Analyses of the samples from the EFG and FBG tests have been• Analyses of the samples from the EFG and FBG tests have been

completed.• The CABRE model was completed in spreadsheet form.

D l t f th d l i t f i l t• Development of the model interface is complete.• Testing of the model beta version is ongoing.


CABRE III Model


Phase III Focus

Spreadsheet Models Graphical User InterfaceSpreadsheet Models Graphical User Interface


Small Pilot-Scale Gasifier Testing

Small Pilot-Scale Gasification Test RunsGasification Test Runs

• Evaluations with sponsor fuels have been completed on EERC small pilot-scale gasifiers:

EFG– EFG• 2750°F (1510°C)• 300 psi (20 atm)300 ps ( 0 a )

– High-pressure FBG• 1800°F (980°C)• 1000 psi (68 atm)

• Focus on ash behavior• Nominal feed rate 8 lb/hr


Bench-Scale Gasification Tests SummarySummary

Fuel Type No. of Days System Run ID Comments

Petcoke 5 Entrained flow EFG026 Shakedown to determine how to slag

Petcoke 3 Entrained flow EFG035 Successfully completed test runPetcoke 3 Entrained flow EFG035 Successfully completed test run

Center 5 Entrained flow EFG028Successfully completed parametric

tests

Falkirk 2 Entrained flow EFG027 Frozen slag in bottom of tube

Falkirk 3 Entrained flow EFG030Successfully completed parametric

tests

Falkirk 5 Fluid bed FBG011Successfully completed parametric

tests


Illinois No. 6 2 Entrained flow EFG029 Coal feed difficulties

Illinois No. 6 3 Entrained flow EFG035Successfully completed parametric

tests

Development of CABRE III Model

Model Objectives

• Partitioning of slag • Mineral transformationsPartitioning of slag and ash

• Viscosity models• Ash deposition• Trace element partitioningViscosity models

• Slag properties• Vanadium

Trace element partitioning• Model inputs• QEMSCAN analysis• Vanadium • QEMSCAN analysis


Model Development ‒ Partitioning

• Partitioning is critical to the model.g• Determination of partitioning:

– Full-scale combustion cyclone slags.– Full-scale gasifier ash.– Bench-scale EFG tests.

G– Bench-scale FBG tests.• Partitioning not strongly linked to process conditions.• Temperature affects partitioning most• Temperature affects partitioning most.


Viscosity Model

Test Slag Calculate ViscosityTest SlagComposition

yIndicators

(5)

Sl D b

Calculate Differences:Composition

Viscosity IndicatorsSlag DatabaseComposition

Viscosity(100+ slags)

Calculate ViscosityIndicators

(5)(100 slags)


Viscosity Model

YesCalculate Differences:

CompositionViscosity Indicators

Close Match inComposition?

Use DatabaseSlag Viscosity

(high confidence)

Yes

No

Cl M h i U D bClose Match inViscosity

Indicators?

Use DatabaseSlag Viscosity

(some confidence)

NoUse

Riboud Viscosity


Riboud ViscosityModel

Slag Viscosity

Molten slag viscosity is measured in a rotating-bob viscometer.


CABRE III Viscosity Model EvaluationEvaluationFalkirk Coal Ash

5.0

4.0

4.5

5.0

e

3.0

3.5

osity, log10

poise

Hoy

Kal

Rib

Sch

1.5

2.0

2.5

Visco Sch

Shaw

Urb

Exp

1.01000 1100 1200 1300 1400 1500

Temperature, °C


Literature Viscosity Models

ModelAv log10 Mean Difference Between Model and

Measured DataHoy 0.286Kalmanovich 0.362Novak 6.279Riboud 0 196Riboud 0.196Schobert 0.407Senior Fe2O3 2.894Senior 50/50 2.922Senior FeO 2.358Shaw 0.432Urbain 0.409Watt–Fereday 1.132Modified Watt–Fereday 0.702Browning, w/S 0.821Browning no S 0 689


Browning, no S 0.689Based on these data, Riboud model the best.

Slag Properties ‒ Flow

Fuel AshComposition

SlagCompositionPartitioning Slag Properties(T)

ViscositySurface TensionComposition p

DensityHeat Capacity

LiquidSolid

ConductivitySolid SlagSolid Slag Liquid SlagLiquid Slag

TT TT TT

GasGasConductivity

LiquidSolid

WallWall

TTwallwall TT250250TTsurface, gassurface, gas

Heat FluxHeat Flux

Slag Flow

Impaction RateImpaction Rate(coal + ash)(coal + ash)


Slag FlowSlag Flow

Model Comparisons

Partitioning Predictions

50

Falkirk Slag

30

40

centage

CABRE Model

0

10

20Perc CABRE Model

Test Run

Falkirk Fly AshSiO₂ Al₂O₃ Fe₂O₃ TiO₂ P₂O₅ CaO MgO Na₂O K₂O SO₃Oxide

30

40

50

geFalkirk Fly Ash

10

20

30

Percen

tag

CABRE Model

Test Run


0SiO₂ Al₂O₃ Fe₂O₃ TiO₂ P₂O₅ CaO MgO Na₂O K₂O SO₃

Oxide

Viscosity Predictions

100

70

80

90

50

60

70

cosity, Pa‐s

Falkirk Coal

d l

20

30

40Visc CABRE Model

CABRE/Riboud

0

10

20

1000 1100 1200 1300 1400 1500 1600 1700 1800


1000 1100 1200 1300 1400 1500 1600 1700 1800Temperature, C

CABRE III User Interface

New Session


Gasifier Definition


Model Results Flow Sheet


Model Results


Deposition


Summary

• CABRE III model works to improve viscosity predictions by d t i i th i it f th l d d ddetermining the viscosity of the slag produced as opposed to using the coal ash chemistry.

• Viscosity is predicted using tables of experimental dataViscosity is predicted using tables of experimental data when available, otherwise the Riboud model is used.

• The beta version of the user interface for CABRE III has been completed and beta testing is under way.

• This is only the beginning of program development.– Many more samples and data sets are needed.– Development of the SABRE IV project is under way.


Contact Information

Energy & Environmental Research CentergyUniversity of North Dakota15 North 23rd Street, Stop 9018Grand Forks North Dakota 58202-9018Grand Forks, North Dakota 58202-9018

World Wide Web: www.undeerc.orgT l h N (701) 777 5087Telephone No. (701) 777-5087Fax No. (701) 777-5181

Josh Stanislowski, Research [email protected]


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