1. 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 NOxby
Chen Zhi-hang Ph.D.
Atmospheric Environment & Pollution Prevention Research Center
South China Institute of Environmental Science, MEP

2. Contents 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

3. Introduction
Beijing
NOx emission
Transportation
Power Plant
Others
Shanghai
Frequency Area%
<5% %
5~10% %
10~25% %
25~50% %
50~75% %
>75% %
No data
Nitrogen oxide emissions from power plants, industrial boilers, and kilns accounted for 70% in China.
(Journal of Environmental Sciences, 2008, 28(12): )
Guangzhou
Acid Rain Distribution in China

4. Technology for DeNOx NH3-SCR DeNOx SCR Adsorption SNCR Method Plasma
Commercialized
High efficient
NH3-SCR
NH3
Plasma
Method
DeNOx
SCR
SCR Reaction:
Microbial
Process
Electrolytic
Process
SCR——selective catalytic reduction
SNCR——selective Non catalytic reduction

5. Mixed-oxide Catalysts for Industrial Boiler at High Temperature

6. SCR for flue gas denitrification in power plant boilers
Honeycomb
Corrugated plate
Flat
SCR
SCR DeNOx Reactor in power plant boilers.
V2O5-WO3(MoO3)/TiO2
The process flow diagram of SCR denitrification in power plant boilers.

7. 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（2008）
Major Scientific and Technological Special Project of Guangdong Province (2010）

8. Demonstration projects of SCR ——Industrial boiler
SCR DeNOx Reactor
Demonstration projects of SCR denitrification
(35 t/h chain-grate boiler in Pacific(Panyu) Textiles Limited, flow rate: Nm3/h )
SCR Denitrification tower of Pacific co.

9. Mixed-oxide Catalysts for SCR at Low Temperature

10. SCR at Low Temperature SCR at 80~150℃ SCR
Energy efficient and cost saving
Typical SCR catalyst has low activity under low temperature
Novel Catalyst should be developed for low temperature
Suitable temperature for catalysis(SCR at 350~450℃)
Dust (e.g., K2O, CaO, and As2O3) and SO2 deactivate the catalyst

11. 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
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[2] Appl. Catal. A 327 (2007) 261.
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[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

12. Activity of mixed oxides prepared by SR method
Screen of Low-temperature SCR Catalysts
Activity of mixed oxides prepared by SR method
Activity evaluation conditions:[NO]=[NH3]=1000 ppm[,O2]=3%,[SO2]=100 ppm,GHSV=30,000 h-1
Cr-MnOx、Fe-MnOx are potential catalysts

13. Cr-MnOx SCR activity at Low temperature
New crystal
SCR activity and XRD patterns of (a) CrOx; (b) MnOx; (c) CrOx-MnOx; (d) Cr(0.5)-MnOx catalysts

14. Cr(0.4)-MnOx
Cr(0.5)-MnOx
Cr(0.4)-MnOx
Cr(0.3)-MnOx
Cr(0.3)-MnOx
Cr(0.2)-MnOx
Cr(0.2)-MnOx
Cr(0.1)-MnOx
Cr(0.1)-MnOx
XRD patterns and SEM images of the Cr-MnOx catalysts doped by different Cr content

15. Mechanism studying ——Cr-MnOx Structure analysis
Cr2O3
CrMn1.5O4
Bond length of crystals
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
Crystal
Bond
Bond-length
Mn3O4
Mn-O
2.2922Å
1.9475Å
2.0142Å
MnO
2.2215Å
Cr2O3
Cr-O
2.0367Å
1.9458Å
CrMn1.5O4
2.3509Å
1.4686Å
Cell of CrMn1.5O4

16. Mechanism studying ——Cr-MnOx Raman spectra measurement
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 and 642.7cm-1 are the characteristic shifts of Cr-O-Mn in CrMn1.5O4
Cr(0.4)-MnOx
Cr(0.3)-MnOx
Cr(0.2)-MnOx
Cr(0.1)-MnOx
Cr2O3[13-15]
Mn3O4[16-18]
MnOx
CrOx
[13] J. Appl. Phys. 99 (2006) ;
[14] Mater. Sci. Eng. B 118 (2005) 74;
[15] J. Appl. Phys. 103 (2008) ;
[16] J. Electrochem. Soc. 140 (1993) 3065;
[17] J. Mater. Chem. 11 (2001) 1269;
[18] J. Catal. 150 (1994) 94
Raman spectra of catalysts

17. Mechanism studying ——Cr-MnOx XPS measurement
Mn 2p
Cr 2p
O 1s
regenerated
used
fresh
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.

18. Mechanism studying ——Cr-MnOx XPS measurement
Binding energies (eV) of core
electrons of Cr(0.4)-MnOx catalysts*
After 500h SCR
Regenerated catalyst
XPS
spectra
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)
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)
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)
Cr5+
Mn3+
7.7%
6.4%
Cr3+
Mn4+
10.6%
7.3%
Cr5+
Mn3+
9.0%
13.7%
Cr3+
Mn4+
11.9%
14.2%
Normal pressure &
temperature plasma treatment
* Surface concentration of different Mn, Cr and O states are in parenthesis

19. Redox catalytic cycles over Cr(0.4)-MnOx catalysts
Mechanism studying
——mechanism elucidation
Redox catalytic cycles over Cr(0.4)-MnOx catalysts
Journal of Catalysis, 2010, 276:
Industrial & Engineering Chemistry Research, 2012, 51:
Industrial & Engineering Chemistry Research, 2014, 53: 2647–2655.

20. Pilot 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）

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

22. Middle-low temperature SCR for glass kilns
Work at 180~300℃
High activity
Strong ability of sulfur tolerant
The process flow diagram of SCR for glass kiln.
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℃)

23. SCR activity of VM/TiO2 catalysts
Screen of Middle-low Temperature SCR Catalysts
SCR activity of VM/TiO2 catalysts

24. Effects of SO2 on NOx conversions over VM/TiO2 catalysts at 275oC.
Effect of SO2
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

25. XPS measurement V4+ V5+ 2V20Cu/TiO2 2V16Cu/TiO2 2V12Cu/TiO2 2V8Cu/TiO2

26. VCuMn/TiO2 & VCoMn/TiO2 Catalysts
SCR activity of VCuMn/TiO2 & VCoMn/TiO2 Catalysts

27. Effect of SO2 VCuMn/TiO2 VCoMn/TiO2
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.
Advanced Materials Research, 2012, :
Journal of Fuel Chemistry and Technology, 2012, 40(4):

28. The vacuum refining mud machine
Forming of Catalysts
The vacuum refining mud machine
Hydraulic extruder
Natural Science Foundation of Guangdong (2011）
National Natural Science Foundation of China （2013）
Pearl River Nova Program of Guangzhou (2014）

29. Conclusion & 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.

30. Thank you for your attention！
Acknowlegment
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 attention！