Understanding thermal processes inUnderstanding thermal processes … · 2018. 1. 12. · Understanding thermal processes inUnderstanding thermal processes in many nanoparticle-related

Understanding thermal processes inUnderstanding thermal processes in many nanoparticle-related applicationsDonggeun Lee,Donggeun Lee, Professor at School of Mechanical Engineering, PNU

Page 1BRL ON DCFC

Summary of on-going researches: what & howSummary of on going researches: what & how

• One step continuous synthesis1

Material Synthesis

• de-NOx & de-SOx catalysts

• Catalytic regneration of DPF

• Sulfur effect on slagging

• One-step continuous synthesis

• Flame, Aerosol-gel, Spray pyrolysis

• Under control of microstructure,

size & compositionENVIROMENT :CATALYSTS

POWER PLANTHYDROGEN

ENERGY : PEMFCDCFC

THERMITES

gg g

•Thermochemical cycle for H2p

• Pt/C & PtRu/C Inks

• Wet-surface electrode

• Energetic combustion

3

Online & Offline

AEROSOL‐BASEDAPPLICATIONS

2

N i l Online & Offline Characterization

INSTRUMENTATION :SPMS

NumericalAnalysis

• CFD : Particle-laden flow

• CFD : Atomization

MC ti & i t t

• Single particle mass spectro.

• T-jump mass spectrometryT‐JUMP MS• MC : aggregation & microstructure

• LB : heterogenueous multi-component

structure

T jump mass spectrometry

• Insitu thermal analyser (hot stage)

• Physicochemical & electrochemical

Page 2BRL ON DCFC

1. Energy 1) Pt catalyzed fuel electrode of PEMFC1. Energy

Key factors for commercialization

1) Pt catalyzed fuel electrode of PEMFC

- long-term reliability- a minimal use of Pt

Potential Solutions Potential Solutions- make smaller Pt particles - enhance Pt surface dispersion

d l t ff ti th d- develop more cost-effective method- find less-expensive catalysts (Ru, Co, Y)

e -H2

e -e -

e -

O2Bip

ola

r Pla

te

An

od

e

Ele

ctro

lyte

Ca

tho

de

Bip

ola

r Pla

teH+

H+

H+

Page 3BRL ON DCFC

O2

1. Energy 1) Pt catalyzed fuel electrode of PEMFC1. Energy 1) Pt catalyzed fuel electrode of PEMFC

a) b)a)a) b)

20 nm20 nm20 nm20 nm

c) d )60

70

60 mm

20 nm20 nm20 nm20 nm20 nm20 nm20 nm20 nm20 nm20 nm

c)c) d )60

70

60 mm

30

40

50

oun

ts

85 mm 120 mm

30

40

50

oun

ts

85 mm 120 mm

0

10

20

Co

0

10

20

Co

Page 4BRL ON DCFC

20 nm20 nm 0 2 4 6 8 10 12 14-10

dp [nm]

20 nm20 nm20 nm20 nm20 nm20 nm 0 2 4 6 8 10 12 14-10

dp [nm]

1. Energy 1) Pt catalyzed fuel electrode of PEMFC1. Energy 1) Pt catalyzed fuel electrode of PEMFC

20

2 adsRu H O Ru OH H e

2ads adsPt CO Ru OH CO Pt Ru H e

10

15 CommercialSynthesis

cm-2 MOR test

0

5

I/mA

c

-50 0.2 0.4 0.6 0.8 1 1.2 1.4

E / V (vs RHE)

*Onset point : 0.61V, 0.65V

0.5

0

cm-2

-0.5

Synthesis

I/mA

c

CO strippingEAS(m2/g) Onset point

Page 5BRL ON DCFC-1

0 0.2 0.4 0.6 0.8 1 1.2

Commercial

E / V (vs RHE)

CO-strippingSynthesis 72.94 0.604V

Commercial 65.67 0.641V

1. Energy 2) Basic Research Lab on DCFC1. Energy 2) Basic Research Lab on DCFC

Anode : C + 2CO32- → 3CO2 + 4e-

C th d O 2CO 4 2CO 2Cathode : O2 + 2CO2 + 4e- → 2CO32-

Net reaction : C + O2 → CO2

• no need of CO2 separationno need of CO2 separation

• Highest theoretical electrochemical efficiency

• easy retrofitting to MCFC or SOFC

till i id d l i t• still in an idea-developing stage

• suffer from limitted triple-phase interfaces

• unknown thermal stabilities of various coals

Page 6BRL ON DCFC


연료공급장치기술

애노드 가공기술

• 주형을 이용한 다공성 전극 제조

MC/CFD 다차원 해석 >기공도제어• 순환형 연료공급장비 설계 및 제작

• 불순물 제거 및 억제기술 개발

• 가스의 확산제거 해석기술

• MC/CFD 다차원 해석->기공도제어

• 삼상계면 형성의 최적 제어기술

애노드 평가 기술

• 애노드 전극의 전해질증발문제 해결

• 산화물코팅을 통한 젖음성 향상

• 고온 전기화학특성 평가• 고온 전기화학특성 평가

열관리 기술석탄 특성 평가

Page 7BRL ON DCFC

• 다공성 전극의 열전달 특성해석

• 용융탄산염의 고온유지(열교환기)

• 유기적제어를 통한 운전최적화

• 미분탄의 탄종별 특성 분석

• 미분탄/용융탄산염 고온특성 최적화

• 석탄의 가스화 특성 해석


Ce (blue) oxygen (green), nickel (red)

CeCl3 + citric acid + ethanol (50ml)

Sol-gel reaction for CeO2 coating0.01mol%(b) (b1)0.01mol%

Ce (blue) oxygen (green), nickel (red)

Stirring_3000ppm (30min)

Ni foam dipped into sol solution for several time 0.1mol%(c) (f)(c1)0.1mol%

Dried at 60℃ for 15min

Calcination at 500℃ for 30minCalcination at 500 ℃ for 30minIn a Ar atomsphere

Page 8BRL ON DCFC


Contact angle: 101.5o

On Ni electrode


CeO2 0.01mol%

Case 1Carbon black


CeO2 0.1mol%

Case 2 Carbon black

Case 3 CeO2

Page 9BRL ON DCFC


Case 1Carbon black

80Data 10

Case 1

Case 2 Carbon black60

70

m2)

Case 3-0.01%)

Case 3 CeO2

40

50

60

ty (

mW

/cm

Case 2

20

30

40

Case 1

C 2ower

den

si

Improved max power density by

10

20 Case 2

Case 3 - 0.01mol%

Case 3 - 0.1mol%

Po

Case 1

Case 3- maximizing triple-phase boundary

- enhancing electrode wetness

Further study00 50 100 150 200 250

Current density (mA/cm2)

Further study

- Test for various coating materials

(better conductivity & stability)

Page 10BRL ON DCFC

1. Energy 3) Energetic materials : Thermite1. Energy 3) Energetic materials : Thermite

Explosives

Al + MO > Al O + M

Rocket propellant

Al + MOx -> Al2O3 + M

O2-free welding

Page 11BRL ON DCFC


Al + MO > Al O + MAl + MOx -> Al2O3 + M

Page 12BRL ON DCFC


Ref [11]: 73.3% of Al volume melts

at bulk Tm-0.5

0.044 nm

a)

Ref. [6]Refs. [8-10]


at bulk Tm

-1.0

-0.5

0.0

(Hea

t Flo

w).

mW

/mg

Calculations

80 nm

Melting pt

Ref. [11][ ]


at bulk Tm

-1.0D

SC

Sig

nal

Experiment

121 nm

-1.0

-0.5

0.0

Page 13BRL ON DCFC

500 550 600 650 700 750

Temperature, o C

b) HR-TEMc) DSC


Page 14BRL ON DCFC


Page 15

2. Environment 1) de-NOx catalysts2. Environment 1) de NOx catalysts

Aerosol-gel process to produce Pt/MOx Pt/SiO2

M

OH

M

MM

MM

MO

OO

O

O

OOO

O

O

O

O

O

O

O

O

O

H H

H

H

H

HHH

H

H

H

H

H H

H

O

O

OO

OO

O

OO

OOOO

OO

OO

O

OOO

O

M

MM

MM

M

M

ROHOHSiHOHORSi hydrolysis

ROHSiOSiORSiOHSi

HOHSiOSiOHSiOHSioncondensatialcohol

oncondensatiwater

HHHHOOO

ROHSiOSiORSiOHSi oncondensatialcohol

20 nm20 nm

Pt/Al2O3

Page 1610 nm

2. Environment 1) de-NOx catalysts2. Environment 1) de NOx catalysts

HydroCarbon-based Selective Catalytic Reduction : aNO+bC3H6+cO2 dN2+eNO2+fN2O+gH2O+hCO23 6 2 2 2 2 g 2 2

0.9

1

1.1

NO

2

O 2O

CO

2

H6

Pt/SiO2

0.9

1

1.1

NO

2

O 2O

CO

2

H6

Pt/Al2O3

0.5

0.6

0.7

0.8

% a

bs (

a.u.

)

NO N

2

C3H

275

300

350

400

0.5

0.6

0.7

0.8

% a

bs (

a.u.

)

NO N

2

C3H

275

300

350

400

0.1

0.2

0.3

0.4%

In le t

150

200

250

275

0.1

0.2

0.3

0.4%

In le t

150

200

250

275

0800 1200 1600 2000 2400 2800

W avenum ber (cm -1)

In le t0800 1200 1600 2000 2400 2800

W avenum ber (cm -1)

In le t

Page 17BRL ON DCFC

2. Environment 1-1) Colloidal system2. Environment 1 1) Colloidal system

Experimental parametersInteraction between

Particle growthExperimental parameterscolloidal particles

Solution (pH, T, I) DLVO theory Suspension stabilityCharged functional

groupHelmholtz plane

Charged functionalgroup

Helmholtz plane

Particle growth

Surface charge state- protonation Kp

- deprotonation Kd

Electrostatic repulsion Van der Waals attraction Total interaction

Particle collision kinetics

-OH2+

-OH

O- C+ A-

C+

A-

Helmholtz plane

A-

A-

H2O-OH2+

-OH

O- C+C+ A-A-

C+C+

A-A-

Helmholtz plane

A-A-

A-A-

H2O 20b

tot

)xr2(

dx

Tk

Eexpr2W

HMOMOH

MOHHMOH

Kd

2KpCuO-O

-OH2+

-OH

-OH2+

A-

C A A

C+

A-

ShearC+

C+CuO

-O

-OH2+

-OH

-OH2+

A-A-

CC AA AA

C+C+

A-A-

ShearC+C+

C+C+

repulsive

W3

Tk8

W

kkk bdiff

diff

Microstructure control 0

d

Shear plane 0

d

Shear plane

repulsive

attractive

0 d sx

0 d

0 d sx

0 d

Page 18BRL ON DCFC

2. Environment 1-1) Colloidal system2. Environment

a)

)

d)

1 1) Colloidal system

b)

c)

e)

f)

400

500

MonomerDimer

200

300

TrimerTetramer8~10mer

r N

um

er(#

)

100

200

Clu

ster

Page 19

00 0.01 0.02 0.03 0.04 0.05

Time (s)

2. Environment 1-2) Link systematic parameters w/ suspension stability2. Environment 1 2) Link systematic parameters w/ suspension stability

pH566.0pH566.0PZC

ptot

pH566.0pH566.0P

PZC

pH566.0pH566.0

tot0 101010

KF

)1010(K/10

1010F

P )(

pH434.0c

pH566.0

pH434.0a

pH566.0

pH566.0pH566.0P

PZCtot

s 10)C(aK1

10

10)A(aK1

10

)1010(K/10

F

pH434.0c

pH566.0

pH434.0a

pH566.0

PZC

ptot

10)C(aK1

10

10)A(aK1

10

10

KF

2d22

3d

ds TR

IF7.1051

RT2

Fsinh

FI4000

pH5660pH566022 1010KTR

pH434.0c

pH566.0

pH434.0a

pH566.0

PZC2Ptot

222d 10)C(aK1

10

10)A(aK1

10

10IF7.1051

KTR

)(2U 2el )xexp(r2U 2dr0

el

)xexp(1010KrRT803.3

UH4340

pH566.0

H4340

pH566.0

PZCPtotel

Page 20

)p(10)C(aK110)A(aK110 pH434.0

cpH434.0

aPZC

BRL ON DCFC

2. Environment 1-2) Link systematic parameters w/ suspension stability2. Environment 1 2) Link systematic parameters w/ suspension stability

)xexp(10)C(aK1

10

10)A(aK1

10

10

KrRT803.3U

pH434.0

pH566.0

pH434.0

pH566.0

PZCPtotel

8(a)

x12

rAU 132vdW

10)C(aK110)A(aK110 ca

4

6

2.05

2.1(b)

x12

rA)xexp(

10)C(aK1

10

10)A(aK1

10

10

KrRT803.3U 132

pH434.0c

pH566.0

pH434.0a

pH566.0

PZCPtot

tot

2

CuO (25nm)

ln W

1 9

1.95

2

fx

)x1(x

)xexp(

dU -2

0CuO (25nm)

SiO2 (25nm)

1.8

1.85

1.9

CuO (25nm)

d f

/X0dx

dUmax

maxx

tot

20 4.25 10-12 8.5 10-12 1.275 10-11 1.7 10-11

|/r/|1.7

1.75

0 4 25 10-12 8 5 10-12 1 275 10-11 1 7 10-11

( )

SiO2 (25nm)

2x

)x1(Umax

maxmax,tot

21U

)Wl ( maxtot

0 4.25 10 8.5 10 1.275 10 1.7 10|/r/|

Page 21

2TkTk

)Wln(bb

max,tot

BRL ON DCFC

2. Environment 2) S effect on slagging2. Environment 2) S effect on slagging

Slagging & Fouling Trouble at Pulverized Coal Fired Boiler

R. Webber et. al., 2011

Ash deposition at furnace wall, super heater & reheater tube surface

• Degrade heat transfer efficiency• Boiler damage by fallen clinker (5 tons)• Blockage at the bottom of PC boiler• Blockage at the bottom of PC boiler

Need to understand the mechanism of

Page 22

the slagging & fouling & clinker formation


As

SpeciesMelting

Point (oC)Element Si Fe Al Ca K Na

At i % 48 29 5 6 11 4 3 2 2 0ICP-AESsh com

pos

Fe2O3 1566

SiO2 1600

CaSO4 1460

MgO 2852

Atomic % 48 29 5.6 11.4 3.2 2.0

Phase Fe2O3 Al2O3 CaSO4

% Mol 58.4 8.6 33XRD

1200°C

ition

MgO 2852

Al2O3 2072

CaO 2572

Major species : glassy SiO2 + Fe2O3+ CaSO4

Minor species : Al2O3 + Alkali metal compounds

1200 C

No. CrystallinePhase

JCPDSNo.

1 CaSO4 86-22701

at 600 oCr2 = 0.91 Peak observation w/ ramping T

CaSO4, Fe2O3, SiO2

2 Al2O3 88-0826

3 Fe2O3 84-0309

4 SiO2 87-2096

5 Ca2Fe2O5 18-0286ensi

ty (

cps)

2

3

4

5

Ca2Fe2O5, CaFe3O5,

CaFe4O7, Fe2SiO4,6 Fe3O4 82-1533

7 Fe2SiO4 [2] 80-1625

8 Fe2SiO4 [1] 87-0315

Inte

6

7

8

9

4 2 4

Fe3O4 at 1100-1150oC

Page 23

9 CaFe3O5 31-0274

20 30 40 50 60 702 (degree)

9

BRL ON DCFC


B l R ti ZHT-XRD Indicates Below Reaction Zone: < 800°C

HT XRD IndicatesZone A

40Zone A Zone B Zone C

C Reaction Zone: 800~1150°C CaSO4 reacts w/ Fe2O3 to form various forms of Calcium ferrite formation

Zone B30

CaSO4Fe2O3Fe3O4CaFe4O7CaFe3O5%

)

o at o

Melting Zone: > 1200°C

C fZone C

20

CaFe3O5Ca2Fe2O5

mo

l (%

Calcium ferrite begins to meltZone C

0

10

Potential Reaction pathway1. CaSO4 + 3Fe2O3 CaF3O5 + Fe3O4 + SO2 + O2

2. CaSO4 + 2Fe2O3 CaFe4O7 + SO2 + 0.5O2

3 2CaSO +Fe O Ca Fe O +SO +2O

0

600 700 800 900 1000 1100 1200 1300

Temperature (oC)

Page 24

3. 2CaSO4+Fe2O3 Ca2Fe2O5+SO2+2O2

4. 2CaSO4+4Fe2O3 Ca2Fe2O5+2Fe3O4+SO2+2.5O2

2. Environment 2-1) Percolation theory, EMT vs LBM2. Environment 2 1) Percolation theory, EMT vs LBM

LBM

EMT

Page 25

2. Environment 3) de-SOx catalysts2. Environment 3) de SOx catalysts

Indirect sulfation Direct sulfation

CaCO3 CaO + CO2↑--------- DecompositionCaCO3 CaO + CO2↑--------- Decomposition

CaO + SO2 + 1/2O2 CaSO4---- SulfationCaCO3 + SO2 + 1/2O2 CaSO4 + CO2↑

0.1CO2(23%)Vertical Isothermal Furnace at 700~1000 oC

Direct-0.1

0

x100

%) Air(100%)

2( )CO2(100%)

Indirect3 104

4 104

CaSO4CaCO3CaO

CaSO3

1000oC

sulfation

Indirectsulfation

-0.4

-0.3

-0.2

Air100 Air+200 SO230 Air+200 SO2+70CO2100CO2

Wei

ght L

oss (

x

Direct

1 104

2 104

Cou

nts

1000oC

900oC

800oC

Indirect

Flu gas condition-0.5

400 500 600 700 800 900 1000

100 CO2

Temp (oC)0

1 104

20 30 40 50 60 70 80 90Angle (2 Theta)

800oC

700oC

Direct

Flu gas conditionㆍT : 800∼1500oCㆍCO2 : 23%

• TGA indicates that T > 800oC to decompose CaCO3

• XRD indicates that below 800oC, Direct sulfation occurs

Page 26

ㆍO2 : 5~6%ㆍN2 : 70~75% BRL ON DCFC

• above 900oC, Indirect sulfation occurs w/ CaSO3 formation

2. Environment 3) de-SOx catalysts2. Environment 3) de SOx catalysts

80DeSOx Performance at Iso-thermal at Vertical Furnance (90mg) 700oC 800oC

60

70

80

No Sample, switching effect700 oC800 oC900 oC%

)

30

40

50 1000 oC

Perfo

rman

ce (%

700oC : size < 1m700oC : size < 1m 800oC: size > 1m800oC: size > 1m

900oC 1000oC

0

10

20

DeS

Ox

P

(C S O)00 2 4 6 8 10 12

Time (min) 900oC : smallest size900oC : smallest size 1000oC : largest size1000oC : largest size

(Ca, S, O)

CaOCaSOO2/1CaSOSOCaOCaCO C1000T4

C1000T23

C900T2

C800T3

oooo

When T > 1000oC,

de SOx (indirect sulfation) efficiency degraded due to sintering & decomposition of CaSO

Page 27BRL ON DCFC

de-SOx (indirect sulfation) efficiency degraded due to sintering & decomposition of CaSO4

2. Environment 4) C-free H2 production2. Environment 4) C free H2 production

Concept of two-step thermo-chemical cycle• Easy scale-up like CFB + CYRO

O2/1ZnZnO

• Low-temperature splitting is possible

• Various MOx can be used

Quenching gas2O2/1ZnZnO

Zn nanoparticlesGeneration Furnace

Carrier gas

Quenching gas

Ar

Flow meter

Filter

Zn

Quenching length, xq

Generation Furnace

a) 100nm 100nmb) 100nm)

22 HZnOOHZn

222 H)1(COZnOOH)1(COZn

a) 100nm b) 100nmc)

Page 28BRL ON DCFC

2. Environment 4) C-free H2 production2. Environment 4) C free H2 production

Carrier gas

Quenching gas Quenching length, xq

Zn nanoparticlesGeneration Furnace

Ar

Flow meter

Filter

Zn

a) 100nm

550

600

650

700

-2

0

2

e [K

]

lo

J > 102 # cc-1 s-1

Nucl.

quenching

Fi

a)

550

600

650

700

-2

0

2

e [K

]

lo

quenching

J > 102 # cc-1 s-1

Nucl. Fi

b)

350

400

450

500

550

-10

-8

-6

-4

Temp. w/ quenchingTemp w/o quenching

PZn

PZn, satT

emp

era

ture

og

10 P

[Pa]

ilter

350

400

450

500

550

-10

-8

-6

-4

Temp. w/ quenchingTemp w/o quenching

PZn

PZn, satT

emp

era

ture

og

10 P

[Pa]

coagulationilter

100nmb)

300 -1215 20 25 30 35 40

Temp. w/o quenching

xq [cm]

300 -1220 30 40 50 60 70

Temp. w/o quenching

xq [cm]

650

700

0

2quenchingc)

• 25cm : nucleation & condensation

450

500

550

600

-8

-6

-4

-2

Pemp

era

ture

[K

]

log

10 P

[Pa

]

J > 102 # cc-1 s-1

Nucl.coagulation

Filter

25cm : nucleation & condensation

• 55cm : nucleation & coagulation

• 85cm : sintered hexahedral crystal

Page 29BRL ON DCFC

100nmc)

300

350

400

-12

-10

-8

20 30 40 50 60 70 80 90 100

Temp. w/ quenching

Zn

PZn, sat

Te

xq [cm]

r

3. Instrumentation 1) SPMS3. Instrumentation 1) SPMS

linear-time-of-flight tube, Z-stuck MicrochannelPlates (MCP) a 500-MHz

200

Na+

(a)

Aerodynamic lens collimate particles to

ti l b ( 1 )

Plates (MCP), a 500-MHz digital oscilloscope

Ion trajectory100

150

ens

ity [a

.u.]

H+ Na2+

Cl+

particle beam (~ 1 mm) that can be intesected with a free firing laser (~0.3 mm)

0

50

Inte

O+

Cl2+

( 0.3 mm)0 10 20 30 40 50

m/z

Particle trajectory

A frequency-doubled Nd:YAGlaser operated at 10 Hz, 532 nm wavelengths laser power

Particle trajectory

allo

catio

n(m

m)

0

5

Page 30

wavelengths, laser power intensity: 1.71010 W/cm2 (~100 mJ/pulse)Distance from barrel inlet (cm)

Rad

ia

0 10 20 30

-5

3. Instrumentation 2) T-jump MS3. Instrumentation 2) T jump MS

Page 31

AcknowledgementAcknowledgement

Page 32

Documents

Understanding thermal processes inUnderstanding thermal processes … · 2018. 1. 12. · Understanding thermal processes inUnderstanding thermal processes in many nanoparticle-related