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 !!