COAL PARTITIONING PROJECT Mineral Transformations in High ...€¦ · CO2+ H2O Gasification Char +...

COAL PARTITIONING PROJECT

Mineral Transformations in High Temperature

Gasification of Gravity and Size Separated Fractions of

a High Volatile Bituminous Coal

Nari Soundarrajan and Sarma V. PisupatiPennsylvania State University

Presentation Identifier (Title or Location), Month 00, 2008

2

Background - Coal Conversion in Gasifier

Coal

Grinding

flyash

slag

Syngas

CO, H2, CO2

H2S, COS, H2O

Excluded

minerals

Coal + included

minerals

Mineral

Transformations

Complex

mixture of

organic and

inorganic

materials

Pyrolysis

CO2+

H2O

Gasification

Char + included

minerals

CO/CO2 Char

fragmentation*Included minerals

Organic Material

Mineral

Transformations

3

Motivation

Entrained flow slagging gasifiers are a high temperature,

high throughput operation [1]…BUT they face….

• Unburned carbon loss and reduction in efficiency [1]

• Flyash carryover to heat recovery units (syngas coolers)

and downstream equipment [1,2]

– Downtime/loss of reliability

• Existing models and tools do not adequately predict flyash

formation/ash deposition [3]

[1] Tampa electric integrated gasification combined cycle project, Project Performane Summary. Tampa. Tampa Electric Co., C. (2004). [2] “Wabash River Coal Gasification Repowering Project”, Wabash River Energy Ltd. Final Technical Report, under DOE Cooperative Agreement DE-FC21-92MC29310, Aug. 2000[3] Yamashita, T., Y. Fujii, et al. (2006). "Modeling of gasification and fragmentation behavior of char particles having complicated structures." Combustion and Flame 146(1-2): 85-94.

4

Particle Population Model for Lab Scale

Particle Partitioning

Syngas

Mineral

Matter

Gravity Separation

Specific gravity

rangesSG1: 1.3 < ρ

SG2: 1.3 < ρ < 1.6

SG3: 1.6 < ρ < 2.6

SG4: ρ > 2.6

Size Separation

Seven size rangesLargest cut: PS1 > 600 µm

Smallest cut: PS7 < 75 µm

5

Coal: Ash Yield Heterogeneity

0

25

50

75

100

0

25

50

75

100

SG1 SG2 SG3 SG4

Pro

po

rtio

n f

rom

d

en

sit

y

Ash

yie

ld W

t%

Ash yield % in Density Fractions

Ash wt%

0

10

20

(2000 -600)

(425 - 600)(212 - 425)(150 - 212)(106 - 150)(75 - 106)(0- 75) Pro

po

rtio

n f

rom

siz

e

frac

tio

n

Va

lue

in

siz

e f

rac

tio

n

Ash yield wt% in Size Fractions

Ash wt,% in size fraction % coal's ash coming from size fraction

• Ash yield varies widely with

density

• Bulk of the ash is in SG3 and

SG4

• Single largest contribution to

total ash yield of coal is from

SG2 (included minerals)

• Size fractions 0-75 µm and 212-

425 µm contribute max towards

the whole coal ash yield

• Ash yield variation with size

fraction in not significant

• Heterogeniety in ash

yield(about)

SG1 - 80 %, SG2 + 80 %

SG3 + 570 % SG4 + 720 %

6

Iron and Sulfur Distribution in Coal

SG1

SG2SG3

SG4

0

25

50

75

100

600425 -600

212 -425

150 -212

106 -150

75 -106

-75

Wt%

Fe2O3 Distribution (on ash basis)

SG1

SG2

SG3SG4

0.0

4.0

8.0

12.0

600425 -600

212 -425

150 - 212

106 -150

75 -106

-75

Wt%

Sulfur Distribution (coal)

7

XRD / CCSEM / Mossbauer

Samples XRD CCSEM Mossbauer**

BSG4 (heaviest,

density > 2.6

g/cc)

Pyrite, Marcasite,

Quartz, Magnetite,

Calcite, Kaolinite (tr)

Potassium silicate,

Pyrite, Pyrrhotite, Oxidized

pyrite, Iron-rich compounds

and Si, Al containing

unclassified compounds

Szomolnokite

Pyrite

Jarosite

Magnetite - A

Magnetite - B

BSG3 (heavy,

density 1.6 - 2.6

g/cc)

Pyrite, Marcasite,

Quartz, Calcite,

Kaolinite, Illite, Sodium

Aluminum silicate,

Jarosite

Quartz, Calcite, Ankerite,

Kaolinite, Montmorillonite,

Mixed Aluminum silicates,

Pyrite, Pyrrhotite, Gypsum

and Si-rich, Ca-rich

unclassified compounds

Jarosite, Fe2+ in clay

and pyrite

** identified iron phases alone

8

PS1

> 600 μm PS2PS3

212-425 μm PS4 PS5 PS6PS7

0-75 μm

BSG1 <1.3 g/cc

Py

AL

BSG2 1.3- 1.6

Py

AL

BSG3 1.6 – 2.6

Py Py PyFine Py/AL mineralsAL AL AL

BSG4 >2.6 g/ccPy Py Py

Fine Py minerals

Particle Class Shortlist

• Agrees well with mineral liberation processes**

• Substantial amount of included mineral matter in SG1, SG2• Py = pyrite, AL: aluminosilicates

( ** Austin, L. G., A. Kalligeris-Skentzos, et al. (1994). Powder Technology 80(2): 147-158)

9

Gasification Tests

Experimental Setup• Ash yield of BSG3 (1.6-2.6 g/cc) and BSG4 (>2.6 g/cc) much higher

than coal.Samples

• BSG3 minerals composed of aluminosilicates and pyrites mostly inincluded form.

• BSG4 minerals composed of pyrites mainly and substantially asexcluded form.

Conditions• Coarse and fines size fractions from BSG3 & BSG4 gasified in

CO2+steam at 1400 C.Chars

BSG3 showed much lower conversion (~56-60%) compared to BSG4(as well as SG1 & SG2), all of which showed 77-82% at 1400C, 1.7 sec

10

MagneMagne

Magne Magne MagneMagneMagne MagneMagneMagne Magne Magne

MagneMagne

Quart

Quart

QuartQuartQuartQuart QuartQuart

QuartQuart QuartQuartQuartQuart

Pyrrh

PyrrhPyrrh PyrrhPyrrhPyrrhPyrrh Pyrrh PyrrhPyrrh PyrrhPyrrhPyrrh

Potas

PotasPotasPotas Potas

Anhyd

Anhyd

AnhydAnhydAnhyd

AnhydAnhydAnhyd Anhyd AnhydAnhyd Anhyd Anhyd AnhydAnhydAnhyd

10 20 30 40 50 60

Two-Theta (deg)

x103

2.0

4.0

6.0

8.0

10.0

12.0

Inte

ns

ity

(Cou

nts

)

[Bsg3ps7char1400C.xrdml] @Phi=180.0

97-003-5000> Magnetite - Fe3O4

04-007-0522> Quartz-alpha - SiO2

97-003-5008> Pyrrhotite - FeS

00-046-0155> Potassium - K2Si14O29·8H2O

97-001-5876> Anhydrite - CaSO4

BSG3PS7

COAL

CHAR 1400C

58% C

conversion

XRD: BSG3 Fines

10 20 30 40 50 60 70

Two-Theta (deg)

0

100

200

300

400

500

Inte

ns

ity

(Cou

nts

)

[bsg3ps7.raw] Bsg3ps7

98-000-0363> Pyrite - FeS2

97-016-2490> Quartz - SiO2

97-004-0543> Calcite - Ca(CO3)

97-002-6756> Marcasite - FeS2

00-007-0157> Forsterite - 2(Mg0.54Fe0.46)O·SiO2

97-016-6963> Illite - (K0.71Ca0.01Na0.01)(Al1.86Mg0.15Fe0.04)((Si3.27Al0.73)O10(OH)2)

97-016-1625> Gypsum - Ca(SO4)(H2O)297-003-0285> Kaolinite - Al2Si2O5(OH)4

11

XRD: BSG3 Coarse

10 20 30 40 50 60

Two-Theta (deg)

x103

2.0

4.0

6.0

8.0

10.0

12.0

Inte

ns

ity

(Co

un

ts)


97-000-0316> Pyrite - FeS2

01-085-0335> Quartz - SiO2

97-001-6710> Calcite - CaCO3

97-000-2057> Gypsum - Ca(SO4)(H2O)298-000-0368> Pyrrhotite - Fe7S8


97-000-4368> Muscovite - K0.77Al1.93(Al0.5Si3.5O10)(OH)200-042-0005> Silicon - (SiO2)x

10 20 30 40 50 60 70

Two-Theta (deg)

0

50

100

150

200

250

300

350

400

450

Inte

ns

ity

(Co

un

ts)


BSG3PS3

COAL

CHAR 1400C

57% C

Conversion

12

XRD: BSG4 Fines

10 20 30 40 50 60 70

Two-Theta (deg)

0

50

100

150

200

250

Inte

ns

ity

(Cou

nts

)


97-000-0316> Pyrite - FeS2

01-085-0335> Quartz - SiO2

97-001-6710> Calcite - CaCO3


00-003-0799> Marcasite - FeS2

01-074-1784> Kaolinite-1A - Al2Si2O5(OH)4

Ma MaMa Ma MaMa Ma

Qu

Qu

QuQuQuQu QuQu QuQu

Py

Py

Py

Py

Py Py

PyPyPyPy

Po

PoPo PoPo PoAn An AnAn AnAnAnAnAn An AnAn An AnAn

Wu

Wu Wu

Ma

Ma

MaMa

Ma

MaMa MaMa MaMa MaMa

Py

Py

PyPy

Py PyPy Py Py

10 20 30 40 50 60

Two-Theta (deg)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Inte

nsity(C

oun

ts)



04-007-0522> Quartz-alpha - SiO 2


00-046-0155> Potassium - K2Si14O29·8H2O

97-001-5876> Anhydrite - CaSO 4

97-002-4696> Wuestite - Fe.942O


00-029-0724> Pyrrhotite-5T - Fe1-xS

BSG4PS7

COAL

CHAR 1400C

80% C

Conversion

13

XRD: BSG4 Coarse

BSG4PS3

Coal

10 20 30 40 50 60

Two-Theta (deg)

0

500

1000

1500

2000

Inte

ns

ity

(Cou

nts

)[slow_Bsg4ps3.raw] slow-Bsg4ps3

MQ

P

Ct

P

PM

M,P

P

P

Ct: CalciteM: MarcasiteP: PyriteQ: Quartz

10 20 30 40 50 60

Two-Theta (deg)

0

1000

2000

3000

4000

5000

6000

7000

Inte

nsity(C

ounts

)


01-085-0335> Quartz - SiO2

97-003-2651> Pyrrhotite - Fe0.91S

97-005-6533> Pyrite - FeS1.92

97-005-1002> FeS - Iron Sulfide

00-038-0248> Sodium - Na -Al2-Si78-O

04-012-0489> Calcite - Ca(CO 3)

00-047-1499> Sodium - Na 2MgSiO4

00-010-0064> Heideite - FeTi 2S4

CHAR 1400C

77% C

Conversion

14

Transformations: Bsg3ps3 and ps7

XRD of Gasification Chars from BSG3PS3 (coarse) BSG3PS7 (fine) Coal Fractions

10 15 20 25 30 35 40 45 50 55 60 652Theta (°)

1600

3600

6400

10000

Inte

nsity (

counts

)

Q

A

AMR

PoM A Po

SiO2

QQ

A

Q: Quartz

AMR: Amorphous hump

A: Anhydrite

Po: Pyrrhotite

M: Magnetite

15

Transformations: Bsg4ps3 and ps7

XRD of Gasification Chars from BSG4PS3 (coarse) BSG4PS7 (fine) Fractions

10 15 20 25 30 35 40 45 50 55 60 652Theta (°)

1600

2500

3600

4900

6400

Inte

nsity (

counts

)

AMR

Q

Ps-

Po

Wu

APo

Ma

Ma

Ma

Ps-

Po

A

Q

Ps-

Q

AMR: Amorphous phase

A: Anhydrite

Ma: Magnetite

Po: Pyrrhotite

Ps-: Sulfur deficient pyrite

Q: Quartz

Wu: Wuestite

16

BSG3 Coal Char

Pyrite, 9.45%

Marcasite, 5.66%

Quartz, 3.59%

Calcite, 2.77%

Kaolinite 1A, 7.97%

Illite, 6.29%

Others + Amorphous, 3.32%

BSG3PS7 Coal

Magnetite, 4.41%

Pyrrhotite, 4.14%

Quartz-alpha, 6.62%

Anhydrite, 2.96%

Potassium silicate, 3.47%

Others + Amorpho

us, 17.77%

BSG3PS7 CHAR 1400 C

Pyrite, 13.34%

Marcasite, 8.31%

Quartz, 2.37%

Calcite, 2.99%

Kaolinite 1A,

11.11%

Illite, 9.02%

Others + Amorphous, 0.33%

BSG3PS3 Coal

Magnetite, 6.31

Pyrrhotite, 5.08

Quartz, 7.12

Anhydrite, 2.33

Silicon dioxide,

9.16

Others + Amorphous , 17.47

BSG3PS3 CHAR 1400 C

1 Bool, L. E., T. W. Peterson, et al. (1995). Combustion and Flame 100(1-2): 262-270.

17

BSG4 Coal Char

18

Crystalline Amorphous

BSG4PS7 Fine Coal

Crystalline Phase% in Coal on mm

basis

% in Char on

whole coal

basis

% Crystallinity

Lost

Iron minerals 70.59

change

to 49.95 29%

Other minerals 11.12

change

to 12.69 -14%

Negative indicates increase in crystalline phases

BSG4PS3 CoarseCoal

Char

Iron minerals 59.89

change

to 22.43 63%

Other minerals 6.84

change

to 3.69 46%

BSG3PS7 Fine Coal

Char

Iron minerals 15.11

change

to 11.04 27%


change

to 13.04 37%

BSG3PS3 CoarseCoal

Char

Iron minerals 21.64

change

to 11.39 47%


change

to 18.61 27%

Changes in crystallinity of mineral phases during gasification in drop tube reactor

19

Summary

• Formation of Sulfur deficient pyrites in SG4 fractions.

• SG3 fractions (coal rich in aluminosilicates and

associated iron minerals) form larger proportion of

amorphous phases1.

• SG4 fines show increase in crystalline phases of non-

iron minerals.

• Coal fractions where iron minerals associate with

aluminosilicates (SG3) show greater propensity to form

amorphous phases.

• Chars from the coarse fractions of both heavier density

fractions show more intermediate phase minerals and higher

amorphous content.

20

Acknowledgments

• This technical work was performed in support of National Energy Technology Laboratory’s ongoing research in Slagging Gasifier Model Development under the RES contract 0004000.2.670.238.002.

• Collaboration of NETL Scientists and use of the facilities at EMS Energy Institute and Materials Research Laboratory, Penn State is appreciated.

• Sample preparation assistance by CONSOL Energy (Library PA) and METSO Minerals (York PA) is appreciated.

Thank you for your time

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