复合氧化物在催化脱硝领域中的研究及应用Research & Application of Mixed Oxides for Selective

Catalytic Reduction of NOx

by

Chen Zhi-hang Ph.D.

Atmospheric Environment & Pollution Prevention Research Center

South China Institute of Environmental Science, MEP

SCIESSCIESContents

Introduction

Mixed-oxide Catalysts for Industrial Boiler at High Temperature

Mixed-oxide Catalysts for SCR at Low Temperature

Mixed-oxide Catalysts for Glass Kilns at Middle-low Temperature

Conclusions & Prospect

SCIESSCIES

<5% 67.4% 5~10% 6.8%10~25% 10.4%25~50% 8.2%50~75% 5.4% >75% 1.8%No data

Frequency Area%

Acid Rain Distribution in China

Introduction

Beijing

Shanghai

Guangzhou

NOx emission

TransportationPower PlantOthers

Nitrogen oxide emissions from power plants, industrial boilers, and kilns accounted for 70% in China.(Journal of Environmental Sciences, 2008, 28(12): 2470-2479)

SCIESSCIESTechnology for DeNOx

DeNOx

SNCRAdsorptionMethod

SCR

ElectrolyticProcess

PlasmaMethod

MicrobialProcess

NH3

NH3-SCR Commercialized

High efficient

3 2 2 2

298

4 4 4 6

1627 /

NO NH O N H O

G kJ mol

SCR Reaction:

SCR——selective catalytic reductionSNCR——selective Non catalytic reduction

SCIESSCIES

Mixed-oxide Catalysts for Industrial Boiler at High Temperature

SCIESSCIES

SCR for flue gas denitrification in power plant boilers

SCR

The process flow diagram of SCR denitrification in power plant boilers.

SCR DeNOx Reactor in power plant boilers.

Honeycomb Corrugated plate Flat

V2O5-WO3(MoO3)/TiO2

SCIESSCIES

Flue gas denitrification pilot test ——Small and medium-sized boiler

The honeycomb SCR catalyst developed by Tsinghua University et. al.

Test device for flue gas denitrification(200 Nm3/h)

National High Technology Research and Development Program of China (2006） Guangdong-Hongkong Project of The Major Breakthroughs in Key Areas （ 200

8） Major Scientific and Technological Special Project of Guangdong Province (201

0）

SCIESSCIES

Demonstration projects of SCR——Industrial boiler

Demonstration projects of SCR denitrification(35 t/h chain-grate boiler in Pacific(Panyu) Textiles Limited, flow rate: 70000 Nm3/h )

SCR Denitrification tower of Pacific co.

SCR DeNOx Reactor

SCIESSCIES

Mixed-oxide Catalysts for SCR at Low Temperature

SCIESSCIESSCR at Low Temperature

Suitable temperature for catalysis(SCR at 350~450 )℃Dust (e.g., K2O, CaO, and As2O3) and SO2 deactivate the catalyst

Energy efficient and cost savingTypical SCR catalyst has low activity under low temperatureNovel Catalyst should be developed for low temperature

SCR

SCRat 80~150℃

SCIESSCIES

[1] Catal. Commun. 8 (2007) 2096.[2] Appl. Catal. A 327 (2007) 261.[3] Catal. Commun. 8 (2007) 329.[4] Appl. Catal. B 79 (2008) 347.[5] Catal. Commun. 8 (2007) 1896.[6] Angew. Chem. Int. Ed. 40 (2001) 2479.

Catalysts Developed for Low-Temperature SCR[1~12]

MnOx 、 MnOx/TiO2 、 CuOx-MnOx and MnOx-CeO2 etc..

Mn-Cu/TiO2 、 Mn-Cr/TiO2 catalysts showed good activity (CNO:

60 ％ , 120oC, NO/NH3 =1 at 0.2%, GHSV=8,000 h-1)

MnOx-CeO2 exhibited well activity(100oC, CNO:~90%, NO/NH3 =1

at 0.2% ， GHSV=42,000 h-1)

Sulfur dioxide and vapour resistant are weak.

Mixed-oxide catalyst may be a kind of prospective low-

temperature SCR candidates

[7] Appl. Catal. B 44 (2003) 217.[8] Catal. Today 111 (2006) 236.[9] Appl. Catal. B 51 (2004) 93.[10] Appl. Catal. B 62 (2006) 265.[11] Chem. Commun. 7 (2003) 848.[12] Ind. & Eng. Chem. Res. 45 (2006) 6444

SCIESSCIESScreen of Low-temperature SCR Catalysts

100 125 150 175 2000

20

40

60

80

100

NO

x con

vers

ion

(%)

Temperature ( oC)

Ni(0.5)-CoOx(SR)(600)

Zr(0.5)-CrOx(SR)(600)

Co(0.5)-CrOx(SR)(600)

Fe(0.5)-CoOx(SR)(600)

100 125 150 175 2000

20

40

60

80

100

NO

x con

vers

ion

(%)

Temperature ( oC)

Sr(0.5)-MnOx(SR)(600)

Co(0.5)-MnOx(SR)(600)

Ni(0.5)-MnOx(SR)(600)

Cr(0.5)-MnOx(SR)(600)

Fe(0.5)-MnOx(SR)(600)

Activity of mixed oxides prepared by SR methodActivity evaluation conditions:[NO]=[NH3]=1000 ppm[,O2]=3%,[SO2]=100 ppm,GHSV=30,000 h-1

Cr-MnOx 、 Fe-MnOx are potential catalysts

SCIESSCIESCr-MnOx SCR activity at Low temperature

SCR activity and XRD patterns of (a) CrOx; (b) MnOx; (c) CrOx-MnOx; (d) Cr(0.5)-MnOx catalysts

New crystal

SCIESSCIES

10 20 30 40 50 60 70 80

◆

Inte

nsity

(a.u

.)

2

▽▽▽ ▽▽▽▽

▽▽▽

▽▽

▽▽ ◆

◆◆◆◆

▽

▼

▼

▼▼▼▼

▼

▼▼

▼ CrMn

1.5O

4 ▽ Mn

3O

4 ◆ MnO

XRD patterns and SEM images of the Cr-MnOx catalysts doped by different Cr content

Cr(0.1)-MnOx

Cr(0.2)-MnOx

Cr(0.3)-MnOx

Cr(0.4)-MnOx

Cr(0.5)-MnOx

Cr(0.1)-MnOx

Cr(0.3)-MnOx

Cr(0.4)-MnOx

Cr(0.2)-MnOx

SCIESSCIES

Mn3O4

Bond length of crystals

Crystal BondBond-length

Mn3O4

Mn-O 2.2922Å

Mn-O 1.9475Å

Mn-O 2.0142Å

MnO Mn-O 2.2215Å

Cr2O3

Cr-O 2.0367Å

Cr-O 1.9458Å

CrMn1.5O4

Mn-O 2.3509Å

Cr-O 1.4686Å

MnO

Cell of CrMn1.5O4

Cr2O3 CrMn1.5O4

Mechanism studying——Cr-MnOx Structure analysis

Oxygen bridge between Cr and Mn in the form of Cr-O-Mn;

Cr-O bond in CrMn1.5O4 is

shorter than those of CrOx

Mn-O bond in CrMn1.5O4 is

longer than those of MnOx

SCIESSCIES

Raman shift of CrOx in lower

wave number without presenting in mixed oxides conforms the formation of new phase;

New Raman shift appears and increases with the increasing of Cr content;

Raman shift at 539.3 and 642.7cm-1 are the characteristic shifts of Cr-O-Mn in CrMn1.5O4

Raman spectra of catalysts

Mechanism studying——Cr-MnOx Raman spectra measurement

CrOx

MnOx

Cr(0.1)-MnOx

Cr(0.2)-MnOx

Cr(0.3)-MnOx

Cr(0.4)-MnOx

Cr(0.5)-MnOx

[13] J. Appl. Phys. 99 (2006) 053909; [14] Mater. Sci. Eng. B 118 (2005) 74; [15] J. Appl. Phys. 103 (2008) 023507; [16] J. Electrochem. Soc. 140 (1993) 3065; [17] J. Mater. Chem. 11 (2001) 1269; [18] J. Catal. 150 (1994) 94

Cr2O3[13-15] Mn3O4

[16-18]

SCIESSCIES

640 645 650 655 660

c

b

Mn4+

Mn3+

Inte

nsi

ty (

a.u

.)

Binding Energy (eV)

Mn2+(A)

a

570 575 580 585 590 595

Cr5+

Cr3+

Inte

nsi

ty (

a.u

.)

Binding Energy (eV)

Cr2+

c

b

a

(B)

525 530 535 540

a

b

Inte

nsi

ty (

a.u

.)

Binding Energy (eV)

(C)O2-

OH-/CO3

2-

c

XPS spectra for (A) Mn 2p, (B) Cr 2p, and (C) O 1s of the Cr(0.4)-MnOx catalysts: (a) fresh catalyst, (b) used catalyst, (c) regenerated

catalyst.

Mn 2p Cr 2p O 1s

fresh

used

regenerated

Mechanism studying——Cr-MnOx XPS measurement

SCIESSCIES

XPSspectra

Element valence

Cr(0.4)-MnOx Catalysts

Fresh Used Regenerated

Cr 2p (eV)Concn(%)

Cr2+ 575.6(13.9) 575.7(16.8) 575.7(19.7)

Cr3+ 576.7(42.2) 576.7(49.9) 576.6(38.0)

Cr5+ 578.4(43.9) 578.3 (33.3) 578.5(42.3)

Mn 2p (eV)

Concn(%)

Mn2+ 640.4(14.6) 640.5(15.5) 640.5(16.0)

Mn3+ 641.9(54.2) 641.9(46.9) 642.2(60.6)

Mn4+ 644.6(31.2) 644.5(37.6) 644.8(23.4)

O 1s (eV) Concn(%)

O2- 529.8(71.0) 529.8(73.9) 529.9(72.2)

OH-/CO32- 531.6(29.0 531.7(26.1) 531.8(27.8)

Binding energies (eV) of core electrons of Cr(0.4)-MnOx catalysts*

* Surface concentration of different Mn, Cr and O states

are in parenthesis

Cr5+

Mn3+

7.7%

6.4%

Cr3+

Mn4+

10.6%

7.3%

After 500h SCR

Cr5+

Mn3+

9.0%

13.7%

Cr3+

Mn4+

11.9%

14.2%

Regenerated catalyst

Normal pressure &

temperature plasma

treatment

Mechanism studying——Cr-MnOx XPS measurement

SCIESSCIES

4 3adsNO Mn NO Mn

3 52 2 adsO Cr Cr O

2ads adsNO O NO

Redox catalytic cycles over Cr(0.4)-MnOx catalysts

Mechanism studying——mechanism elucidation

2Mn4+2Mn3+

Cr3+Cr5+

O2 O-ads2

NO+adsNO 22

Redox

Reaction

NO22Electronic transferCrMn1.5O4

5 3 3 42 2Cr Mn Cr Mn

Journal of Catalysis, 2010, 276: 56-65.Industrial & Engineering Chemistry Research, 2012, 51: 202-212.Industrial & Engineering Chemistry Research, 2014, 53: 2647–2655.

SCIESSCIESPilot test of Low-temperature SCR

The Low-temperature SCR catalyst developed by Research Center for Eco-environmental Science, CAS et. al. Test device for Low-

temperature SCR(Circulating fluidized bed boiler in Guangzhou Huiteng Textiles Limited, flow rate: 5000 Nm3/h )

National Natural Science Foundation of China （ 2008） National High Technology Research and Development Program

of China (2009）

SCIESSCIES

Mixed-oxide Catalysts for Glass Kilns at Middle-low Temperature

SCIESSCIES

The process flow diagram of SCR for glass kiln.

Middle-low temperature SCR for glass kilns

Middle-low temperature SCRWork at 180~300℃High activityStrong ability of sulfur tolerant

The flue gas emission from glass kiln of China South Glass Group(Guangzhou)(The concentration of SO2 、 NOx is very high(about 500~3000mg/m3) The temperature of flue gas is low( ＜ 280℃)

SCIESSCIES

SCR activity of VM/TiO2 catalysts

200 225 250 275 300 325 3500

10

20

30

40

50

60

70

80

90

100

NO

x co

nv

ersi

on

(%

)

Temperature (oC)

2V8Co/TiO2(F)

2V8Fe/TiO2(F)

2V8Ni/TiO2(F)

2V8Cu/TiO2(F)

2V8Mn/TiO2(F)

3V7Mn/TiO2(F)

3V7Fe/TiO2(F)

3V7Cu/TiO2(F)

Screen of Middle-low Temperature SCR Catalysts

SCIESSCIES

Effects of SO2 on NOx conversions over VM/TiO2 catalysts at 275oC. Reaction conditions: [NO]=[NH3]=1000 ppm, [O2]=3%, [SO2]=600 ppm, GHSV=60,000 h-1

1h 2h 3h 4h0

10

20

30

40

50

60

70

80

90

100

NO

x c

on

ve

rsio

n (

%)

Time (h)

2V8Co/TiO2(F)

2V8Fe/TiO2(F)

2V8Ni/TiO2(F)

2V8Cu/TiO2(F)

2V8Mn/TiO2(F)

3V7Mn/TiO2(F)

3V7Fe/TiO2(F)

3V7Cu/TiO2(F)

Effect of SO2

SCIESSCIESXPS measurement

2V8Cu/TiO2

2V12Cu/TiO2

2V20Cu/TiO2

2V16Cu/TiO2

2V2Cu/TiO2

V4+

V5+

SCIESSCIESVCuMn/TiO2 & VCoMn/TiO2 Catalysts

SCR activity of VCuMn/TiO2 & VCoMn/TiO2 Catalysts

200 225 250 275 300 325 3500

10

20

30

40

50

60

70

80

90

100

NO

x c

on

ve

rsio

n (

%)

Temperature (oC)

2V1Cu9Mn/TiO2(F)

2V2Cu8Mn/TiO2(F)

2V3Cu7Mn/TiO2(F)

2V5Cu5Mn/TiO2(F)

2V8Cu2Mn/TiO2(F)

200 225 250 275 300 325 3500

20

40

60

80

100

NO

x c

on

ve

rsio

n (

%)

Temperature ( oC)

2V1Co9Mn/TiO2(F)

2V2Co8Mn/TiO2(F)

2V3Co7Mn/TiO2(F)

2V4Co6Mn/TiO2(F)

2V5Co5Mn/TiO2(F)

2V6Co4Mn/TiO2(F)

2V7Co3Mn/TiO2(F)

2V8Co2Mn/TiO2(F)

2V9Co1Mn/TiO2(F)

VCuMn/TiO2 VCoMn/TiO2

SCIESSCIES

Effects of SO2 on NOx conversions over VCuMn/TiO2 & VCoMn/TiO2 catalysts at 250oC. Reaction conditions: [NO]=[NH3]=1000 ppm, [O2]=3%, [SO2]=600 ppm, GHSV=60,000 h-1.

1 2 3 40

20

40

60

80

100

2V1Cu9Mn/TiO2(F)

2V2Cu8Mn/TiO2(F)

2V3Cu7Mn/TiO2(F)

2V5Cu5Mn/TiO2(F)

2V8Cu2Mn/TiO2(F)

NO

x c

on

ve

rsio

n (

%)

Time (h)

1 2 3 40

20

40

60

80

100

2V1Co9Mn/TiO2(F)

2V2Co8Mn/TiO2(F)

2V3Co7Mn/TiO2(F)

2V4Co6Mn/TiO2(F)

2V5Co5Mn/TiO2(F)

2V6Co4Mn/TiO2(F)

2V7Co3Mn/TiO2(F)

2V8Co2Mn/TiO2(F)

2V9Co1Mn/TiO2(F)

NO

x c

on

ve

rsio

n (

%)

Time (h)

VCuMn/TiO2 VCoMn/TiO2

Effect of SO2

Advanced Materials Research, 2012, 550-553: 128-131. Journal of Fuel Chemistry and Technology, 2012, 40(4):469-474.

SCIESSCIESForming of Catalysts

Natural Science Foundation of Guangdong (2011） National Natural Science Foundation of China （ 201

3） Pearl River Nova Program of Guangzhou (2014）

The vacuum refining mud machine

Hydraulic extruder

SCIESSCIESConclusion & Prospect

Localization of Commercial SCR catalyst has been made progress. How to reduce the cost of catalyst, establish of catalyst regeneration center.

Novel Cr-MnOx, Fe-MnOx, Mn-Zr catalysts with well low-temperature SCR activity have been developed; If we can not solve the problem of high activity at low temperature( ＜ 120℃) ， should we change our thinking.

Series of VMn, VCu, and modified catalysts are studying systematically. How to improve the activity of the catalyst under high concentration of SO2 is a huge challenge.

AcknowlegmentAcknowlegment Ministry of Environmental Protection, China

Ministry of Science Technology, China

National Natural Science Foundation of China

Natural Science Foundation of Guangdong, China

Department of science and technology of Guangdong Province

Department of science and information technology of Guangzhou

South China University of Technology

Thank you for your attentionThank you for your attention ！！