Presentation on theme: "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 &"— Presentation transcript:
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 NOx byChen Zhi-hang Ph.D.Atmospheric Environment & Pollution Prevention Research CenterSouth China Institute of Environmental Science, MEP
2Contents Introduction Mixed-oxide Catalysts for Industrial Boiler at High TemperatureMixed-oxide Catalysts for SCR at Low TemperatureMixed-oxide Catalysts for Glass Kilns at Middle-low TemperatureConclusions & Prospect
3IntroductionBeijingNOx emissionTransportationPower PlantOthersShanghaiFrequency Area%<5% %5~10% %10~25% %25~50% %50~75% %>75% %No dataNitrogen oxide emissions from power plants, industrial boilers, and kilns accounted for 70% in China.(Journal of Environmental Sciences, 2008, 28(12): )GuangzhouAcid Rain Distribution in China
4Technology for DeNOx NH3-SCR DeNOx SCR Adsorption SNCR Method Plasma CommercializedHigh efficientNH3-SCRNH3PlasmaMethodDeNOxSCRSCR Reaction:MicrobialProcessElectrolyticProcessSCR——selective catalytic reductionSNCR——selective Non catalytic reduction
5Mixed-oxide Catalysts for Industrial Boiler at High Temperature
6SCR for flue gas denitrification in power plant boilers HoneycombCorrugated plateFlatSCRSCR DeNOx Reactor in power plant boilers.V2O5-WO3(MoO3)/TiO2The process flow diagram of SCR denitrification in power plant boilers.
7Flue 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）
8Demonstration projects of SCR ——Industrial boiler SCR DeNOx ReactorDemonstration 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.
10SCR at Low Temperature SCR at 80~150℃ SCR Energy efficient and cost savingTypical SCR catalyst has low activity under low temperatureNovel Catalyst should be developed for low temperatureSuitable temperature for catalysis(SCR at 350~450℃)Dust (e.g., K2O, CaO, and As2O3) and SO2 deactivate the catalyst
11Catalysts 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 Catal. Commun. 8 (2007) 2096. Appl. Catal. A 327 (2007) 261. Catal. Commun. 8 (2007) 329. Appl. Catal. B 79 (2008) 347. Catal. Commun. 8 (2007) 1896. Angew. Chem. Int. Ed. 40 (2001) 2479. Appl. Catal. B 44 (2003) 217. Catal. Today 111 (2006) 236. Appl. Catal. B 51 (2004) 93. Appl. Catal. B 62 (2006) 265. Chem. Commun. 7 (2003) 848. Ind. & Eng. Chem. Res. 45 (2006) 6444
12Activity of mixed oxides prepared by SR method Screen of Low-temperature SCR CatalystsActivity of mixed oxides prepared by SR methodActivity evaluation conditions:[NO]=[NH3]=1000 ppm[,O2]=3%,[SO2]=100 ppm,GHSV=30,000 h-1Cr-MnOx、Fe-MnOx are potential catalysts
13Cr-MnOx SCR activity at Low temperature New crystalSCR activity and XRD patterns of (a) CrOx; (b) MnOx; (c) CrOx-MnOx; (d) Cr(0.5)-MnOx catalysts
14Cr(0.4)-MnOxCr(0.5)-MnOxCr(0.4)-MnOxCr(0.3)-MnOxCr(0.3)-MnOxCr(0.2)-MnOxCr(0.2)-MnOxCr(0.1)-MnOxCr(0.1)-MnOxXRD patterns and SEM images of the Cr-MnOx catalysts doped by different Cr content
15Mechanism studying ——Cr-MnOx Structure analysis Cr2O3CrMn1.5O4Bond length of crystalsOxygen bridge between Cr and Mn in the form of Cr-O-Mn;Cr-O bond in CrMn1.5O4 is shorter than those of CrOxMn-O bond in CrMn1.5O4 is longer than those of MnOxCrystalBondBond-lengthMn3O4Mn-O2.2922Å1.9475Å2.0142ÅMnO2.2215ÅCr2O3Cr-O2.0367Å1.9458ÅCrMn1.5O42.3509Å1.4686ÅCell of CrMn1.5O4
16Mechanism 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 CrMn1.5O4Cr(0.4)-MnOxCr(0.3)-MnOxCr(0.2)-MnOxCr(0.1)-MnOxCr2O3[13-15]Mn3O4[16-18]MnOxCrOx J. Appl. Phys. 99 (2006) ; Mater. Sci. Eng. B 118 (2005) 74; J. Appl. Phys. 103 (2008) ; J. Electrochem. Soc. 140 (1993) 3065; J. Mater. Chem. 11 (2001) 1269; J. Catal. 150 (1994) 94Raman spectra of catalysts
17Mechanism studying ——Cr-MnOx XPS measurement Mn 2pCr 2pO 1sregeneratedusedfreshXPS 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.
18Mechanism studying ——Cr-MnOx XPS measurement Binding energies (eV) of coreelectrons of Cr(0.4)-MnOx catalysts*After 500h SCRRegenerated catalystXPSspectraElementvalenceCr(0.4)-MnOx CatalystsFreshUsedRegeneratedCr 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(29.0531.7(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
20Pilot 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）
21Mixed-oxide Catalysts for Glass Kilns at Middle-low Temperature
22Middle-low temperature SCR for glass kilns Work at 180~300℃High activityStrong ability of sulfur tolerantThe 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℃)
23SCR activity of VM/TiO2 catalysts Screen of Middle-low Temperature SCR CatalystsSCR activity of VM/TiO2 catalysts
24Effects of SO2 on NOx conversions over VM/TiO2 catalysts at 275oC. Effect of SO2Effects 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
27Effect 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):
28The vacuum refining mud machine Forming of CatalystsThe vacuum refining mud machineHydraulic extruderNatural Science Foundation of Guangdong (2011）National Natural Science Foundation of China （2013）Pearl River Nova Program of Guangzhou (2014）
29Conclusion & ProspectLocalization 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.
30Thank you for your attention！ AcknowlegmentMinistry of Environmental Protection, ChinaMinistry of Science Technology, ChinaNational Natural Science Foundation of ChinaNatural Science Foundation of Guangdong, ChinaDepartment of science and technology of Guangdong ProvinceDepartment of science and information technology of GuangzhouSouth China University of TechnologyThank you for your attention！