Fe-Ag/Al_2O_3催化丙烯还原NO的实验研究
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摘要
以蜂窝状陶瓷为载体,采用溶胶凝胶法和浸渍法制备了不同Fe/Ag负载量的Fe-Ag/Al_2O_3催化剂。以C_3H_6为还原剂,在模拟烟气条件下和200-700℃范围内,程序控温的陶瓷管流动反应器上进行了催化还原NO的性能评估。结果表明,7.2Fe/1.9Ag/20Al_2O_3/CM在500和550℃时催化C_3H_6还原NO的脱硝效率分别超过90%和达到100%。铁离子能有效地提高Ag/20Al_2O_3/CM催化剂抵抗烟气中的SO_2和H_2O的能力。结果表明,当烟气中含有体积分数为0.02%的SO2和8%的H_2O时,在500℃时7.2Fe/1.9Ag/20Al_2O_3/CM催化C_3H_6还原NO的脱硝效率不受影响,在6 h的连续实验中保持90%的脱硝效率而没有下降。而未经铁离子修饰的2Ag/20Al_2O_3/CM的催化活性则受烟气中的SO2和H_2O影响很大,0.02%的SO2和8%的H_2O分别使2Ag/20Al_2O_3/CM在500℃时催化C_3H_6还原NO的脱硝效率迅速从70%分别下降至46%和25%。XRD和SEM表征结果表明,经铁离子修饰后的7.2Fe/1.9Ag/20Al_2O_3/CM催化剂中,形成了AgFeO_2以及Fe~(3+),催化剂表面变得疏松多孔,形成以Fe_3O_4为主的针状和片状晶体。H_2-TPR结果表明,7.2Fe/1.9Ag/20Al_2O_3/CM比Ag/20Al_2O_3/CM在更宽的温度范围内具有更好的还原特性。吡啶吸附红外光谱(Py-FTIR)实验结果显示,Fe增加了催化剂表面的Lewis酸性位。
Sol-gel and impregnation methods were used to prepare the Fe/Ag/Al_2O_3 catalysts supported on the monolithic cordierite with different Fe/Ag loading ratios. The catalytic performance to reduce NO with C_3H_6 was evaluated in a one-dimensional electrically heated temperature programmed ceramic tubular reactor in simulated flue gas atmosphere at 200-700 ℃. The results showthat the NO reduction efficiency on 7.2 Fe/1.9 Ag/20 Al_2O_3/CMwith C_3H_6 is more than 90% and reaches about 100% at the temperatures of 500 ℃ and 550 ℃ respectively.Iron can effectively improve the ability of Ag/20 Al_2O_3/CMcatalysts to resist SO_2 and H_2O in flue gas. When SO2 and H_2O are 0.02% and 8% in the flue gas,the NO reduction efficiency is almost not influenced on 7.2 Fe/1.9 Ag/20 Al_2O_3/CMat 500 ℃. The 90% NO reduction efficiency is maintained during 6 h without decrease.However,the catalytic activity of 2 Ag/20 Al_2O_3/CMwithout iron modification is strongly influenced by SO_2 and H_2O in the flue gas. The NO reduction efficiency on Ag/20 Al_2O_3/CMdecreases rapidly from about 70% to 46%and 25% respectively,when the SO_2 and H_2O are 0.02% and 8% in the flue gas. The results of XRD and SEMof the catalyst showthat Ag FeO_2 and Fe~(3+) are formed in the 7. 2 Fe/1. 9 Ag/20 Al_2O_3/CMcatalyst after the modification by iron,and the surface of the catalyst become loose and porous,forming Fe3 O4-based needle-like and flaky crystals. H_2-TPR results showthat 7. 2 Fe/1. 9 Ag/20 Al_2O_3/CMhas better reduction properties than Ag/20 Al_2O_3/CMin the wider temperature range. Pyridine adsorption Infrared Spectroscopy( Py-FTIR)experimental results showthat Fe increases the Lewis acid sites in the catalyst surface.
Sol-gel and impregnation methods were used to prepare the Fe/Ag/Al_2O_3 catalysts supported on the monolithic cordierite with different Fe/Ag loading ratios. The catalytic performance to reduce NO with C_3H_6 was evaluated in a one-dimensional electrically heated temperature programmed ceramic tubular reactor in simulated flue gas atmosphere at 200-700 ℃. The results showthat the NO reduction efficiency on 7.2 Fe/1.9 Ag/20 Al_2O_3/CMwith C_3H_6 is more than 90% and reaches about 100% at the temperatures of 500 ℃ and 550 ℃ respectively.Iron can effectively improve the ability of Ag/20 Al_2O_3/CMcatalysts to resist SO_2 and H_2O in flue gas. When SO2 and H_2O are 0.02% and 8% in the flue gas,the NO reduction efficiency is almost not influenced on 7.2 Fe/1.9 Ag/20 Al_2O_3/CMat 500 ℃. The 90% NO reduction efficiency is maintained during 6 h without decrease.However,the catalytic activity of 2 Ag/20 Al_2O_3/CMwithout iron modification is strongly influenced by SO_2 and H_2O in the flue gas. The NO reduction efficiency on Ag/20 Al_2O_3/CMdecreases rapidly from about 70% to 46%and 25% respectively,when the SO_2 and H_2O are 0.02% and 8% in the flue gas. The results of XRD and SEMof the catalyst showthat Ag FeO_2 and Fe~(3+) are formed in the 7. 2 Fe/1. 9 Ag/20 Al_2O_3/CMcatalyst after the modification by iron,and the surface of the catalyst become loose and porous,forming Fe3 O4-based needle-like and flaky crystals. H_2-TPR results showthat 7. 2 Fe/1. 9 Ag/20 Al_2O_3/CMhas better reduction properties than Ag/20 Al_2O_3/CMin the wider temperature range. Pyridine adsorption Infrared Spectroscopy( Py-FTIR)experimental results showthat Fe increases the Lewis acid sites in the catalyst surface.
引文
[1]HELD W,KNIG A,RICHTER T,PUPPE L.Catalytic NOxreduction in net oxidizing exhaust gas[J].SAE Trans,1990,99(4):209-216.
[2]MIYADERA T,YOSHIDA K.Alumina-supported catalysts for the selective reduction of nitric oxide by propene[J].Chem Lett,1993,2(9):1483-1486.
[3]WANG J,HE H,FENG Q,YU Y,YOSHIDA K.Selective catalytic reduction of NOxw ith C3H6over an Ag/Al2O3catalyst w ith a small quantity of noble metal[J].Catal Today,2004,93-95:783-789.
[4]CHAIEB T,DELANNOY L,LOUIS C,THOMAS C.On the origin of the optimum loading of Ag on Al2O3in the C3H6-SCR of NOx[J].Appl Catal B:Environ,2013,142-143:780-784.
[5]THOMAS C.On an additional promoting role of hydrogen in the H2-assisted C3H6-SCR of NOxon Ag/Al2O3:A lowering of the temperature of formation-decomposition of the organo-NOxintermediates[J].Appl Catal B:Environ,2015,162:454-462.
[6]KIM P S,KIM M K,CHO B K,NAM I S,OH S H.Effect of H2on de NOxperformance of HC-SCR over Ag/Al2O3:Morphological,chemical,and kinetic changes[J].J Catal,2013,301(5):65-76.
[7]XIE S,WANG J,HE H.Poisoning effect of sulphate on the selective catalytic reduction of NOxby C3H6over Ag-Pd/Al2O3[J].J Mol Catal A:Chem,2007,266(1/2):166-172.
[8]BURCH R,WATLING T C.The effect of promoters on Pt/Al2O3catalysts for the reduction of NO by C3H6under lean-burn conditions[J].Appl Catal B:Environ,1997,11(2):207-216.
[9]SALEM I,COURTOIS X,CORBOS E C,MARECOT P,DUPREZ D.NO conversion in presence of O2,H2O and SO2:Improvement of a Pt/Al2O3catalyst by Zr and Sn,and influence of the reducer C3H6or C3H8[J].Catal Commun,2008,9(5):664-669.
[10]GOULA M A,CHARISIOU N D,PAPAGERIDIS K N,DELIMITIS A,PAPISTA E,PACKATOURIDOU E,ILIOPOULOU E F,M ARNELLOS G,KONSOLAKIS M,YENTEKIS I V.A comparative study of the H2-assisted selective catalytic reduction of nitric oxide by propene over noble metal(Pt,Pd,Ir)/γ-Al2O3catalysts[J].J Environ Chem Eng,2016,4(2):1629-1641.
[11]MORE P M,NGUYEN D L,DONARE M K,UMBARKAR S B,GRANGER P,DUJARDIN C.Activation by pretreatment of Ag-Au/Al2O3bimetallic catalyst to improve low temperature HC-SCR of NOxfor lean burn engine exhaust[J].Appl Catal B:Environ,2015,174:145-156.
[12]MORE P M,NGUYEN D L,DONGARE M K,UMBARKAR S B,NUNS N,GIRARDON J S,DUJARDIN C,LANCELOT C,M AM EDE A S,GRANGER P.Rational preparation of Ag and Au bimetallic catalysts for the hydrocarbon-SCR of NOx:Sequential deposition vs.coprecipitation method[J].Appl Catal B:Environ,2015,162:11-20.
[13]MORE P M,JAGTAP N,KULAL A B,DONGARE M K,UMBARKER S B.Magnesia doped Ag/Al2O3-Sulfur tolerant catalyst for low temperature HC-SCR of NOx[J].Appl Catal B:Environ,2014,144:408-415.
[14]周皞,廖文裕,苏亚欣,林辛越.H2O和SO2对甲烷在金属铁表面还原NO的影响[J].洁净煤技术,2015,21(2):51-55.(ZHOU Hao,LIAO Wen-yu,SU Ya-xin,LIN Xin-yue.Influence of H2O and SO2on NO reduction by methane on the surface of iron[J].Clean Coal Technol,2015,21(2):51-55.)
[15]ZHOU H,SU Y X,LIAO W Y,ZHONG F C.NO reduction by propane over monolithic cordierite-based Fe/Al2O3catalyst:Reaction mechanism and effect of H2O/SO2[J].Fuel,2016,182:352-360.
[16]ZHOU H,SU Y X,LIAO W Y,ZHONG F C.Preparation,characterization,and properties of monolithic Fe/Al2O3/cordierite catalysts for NO reduction w ith C2H6[J].Appl Catal A:Gen,2015,505:402-409.
[17]KYRIIENKO P,POPOVYCH N,SOLOVIEV S,ORLYK S,DZWIGAJ S.Remarkable Activity of Ag/Al2O3/cordierite catalysts in SCR of NO w ith ethanol and butanol[J].Appl Catal B:Environ,2013,140/141(2):691-699.
[18]苏亚欣,任立铭,苏阿龙,邓文义.甲烷在金属铁及氧化铁表面还原NO的研究[J].燃料化学学报,2013,41(11):1393-1400.(SU Ya-xin,REN Li-ming,SU A-long,DENG Wen-yi.NO reduction by methane on the surface of iron oxides[J].J Fuel Chem Technol,2013,41(11):1393-1400.)
[19]苏亚欣,陆哲惺,周皞,窦逸峰,邓文义.丙烷在金属铁表面还原NO的实验研究[J].燃料化学学报,2014,42(12):1470-1477.(SU Ya-xin,LU Zhe-xing,ZHOU Hao,DOU Yi-feng,DENG Wen-yi.Experimental study on NO reduction by propane over iron[J].J Fuel Chem Technol,2014,42(12):1470-1477.)
[20]窦逸峰,苏亚欣,陆哲惺,周皞,邓文义.乙烷在金属铁表面还原NO的实验研究[J].燃料化学学报,2015,42(10):1273-1280.(DOU Yi-feng,SU Ya-xin,LU Zhe-xing,ZHOU Hao,DENG Wen-yi.Experimental study of NO reduction by ethane over iron[J].J Fuel Chem Technol,2015,42(10):1273-1280.)
[21]ZHOU H,LI K K,ZHAO B T,DENG W Y,SU Y X,ZHONG F C.Surface properties and reactivity of Fe/Al2O3/cordierite catalysts for NO reduction by C2H6:Effects of calcination temperature[J].Chem Eng J,2017,326:737-744.
[22]PUJILAKSONO B,JONSSON T,HALVARSSON M,SVENSSON J E,JOHANSSON L G.Oxidation of iron at 400-600℃in dry and wet O[J].Corros Sci,2010,52(5):1560-1569.
[23]SU J H,LIU Q Y,LIU Z Y,HUANG Z G.Honeycomb Cu O/Al2O3/cordierite catalyst for selective catalytic reduction of NO by NH3-Effect of Al2O3coating[J].Ind Eng Chem Res,2008,47(13):4295-4301.
[24]KYRIIENKO P,POPOVYCH N,SOLOVIEV S,ORLYK S,DZWIGAJ S.Remarkable Activity of Ag/Al2O3/cordierite catalysts in SCR of NO w ith ethanol and butanol[J].Appl Catal B:Environ,2013,140-141(2):691-699.
[25]KUL'KO E V,IVANOVA A S,LITVAK G S,KRYUKOVA G N,TSYBULYA S V.Preparation and microstruc-tural and textural characterization of single-phase aluminum oxides[J].Kinet Catal,2004,45(5):714-721.
[26]KOUOTOU P M,TIAN Z Y,VIEKER H,BEYER A,GLZHUSER A,KOHSEHINGHAUS K.Selective Synthesis ofα-Fe2O3thin films and effect of the deposition temperature and lattice oxygen on the catalytic combustion of propene[J].J M ater Chem A,2013,1(35):10495-10504.
[27]GONZLEZ-VELASCO J R,FERRET R,LPEZ-FONSECA R,GUTIRREZ-ORTIZ M A.Influence of particle size distribution of precursor oxides on the synthesis of cordierite by solid-state reaction[J].Pow der Technol,2005,153(1):34-42.
[28]POPOVICH N A,KIRIIENKO P I,SOLOV’EV S A,ORLIK S N,DZWIGAJ S.Role of active components of an Ag/Al2O3/cordierite catalyst in selective reduction of NO by ethanol[J].Theor Exp Chem,2012,48(4):258-264.
[29]SATOSHI S,MIKA S,MASATAKA F.Enhancing effect of water vapor on the reduction of lean NOx by ethanol over an Ag/Al2O3catalyst supported on cordierite honeycomb[J].React Kinet Catal Lett,1998,64(2):239-246.
[30]ZHANG R,KALIAGUINE S.Lean reduction of NO by C3H6over Ag/alumina derived from Al2O3,Al OOH and Al(OH)3[J].Appl Catal B:Environ,2008,78(3/4):275-287.
[31]RIEDEL T,CLAEYS M,SCHULZ H,SCHAUB G,NAM S S,JUN K W,CHOI M J,KISHAN G,LEE K W.Comparative study of Fischer-Tropsch synthesis w ith H2/CO and H2/CO2syngas using Fe-and Co-based catalysts[J].Appl Catal A:Gen,1999,186(1/2):201-213.
[32]LI J H,ZHU Y Q,RUI K,HAO J M.Improvement of catalytic activity and sulfur-resistance of Ag/Ti O2-Al2O3for NO reduction w ith propene under lean burn conditions[J].Appl Catal B:Environ,2008,80(3):202-213.
[33]WILLIAMS M F,FONFB,SIEVERS C.Hydrogenation of tetralin on silica-alumina-supported Pt catalysts I.Physicochemical characterization of the catalytic materials[J].J Catal,2012,251(2):485-496.
[2]MIYADERA T,YOSHIDA K.Alumina-supported catalysts for the selective reduction of nitric oxide by propene[J].Chem Lett,1993,2(9):1483-1486.
[3]WANG J,HE H,FENG Q,YU Y,YOSHIDA K.Selective catalytic reduction of NOxw ith C3H6over an Ag/Al2O3catalyst w ith a small quantity of noble metal[J].Catal Today,2004,93-95:783-789.
[4]CHAIEB T,DELANNOY L,LOUIS C,THOMAS C.On the origin of the optimum loading of Ag on Al2O3in the C3H6-SCR of NOx[J].Appl Catal B:Environ,2013,142-143:780-784.
[5]THOMAS C.On an additional promoting role of hydrogen in the H2-assisted C3H6-SCR of NOxon Ag/Al2O3:A lowering of the temperature of formation-decomposition of the organo-NOxintermediates[J].Appl Catal B:Environ,2015,162:454-462.
[6]KIM P S,KIM M K,CHO B K,NAM I S,OH S H.Effect of H2on de NOxperformance of HC-SCR over Ag/Al2O3:Morphological,chemical,and kinetic changes[J].J Catal,2013,301(5):65-76.
[7]XIE S,WANG J,HE H.Poisoning effect of sulphate on the selective catalytic reduction of NOxby C3H6over Ag-Pd/Al2O3[J].J Mol Catal A:Chem,2007,266(1/2):166-172.
[8]BURCH R,WATLING T C.The effect of promoters on Pt/Al2O3catalysts for the reduction of NO by C3H6under lean-burn conditions[J].Appl Catal B:Environ,1997,11(2):207-216.
[9]SALEM I,COURTOIS X,CORBOS E C,MARECOT P,DUPREZ D.NO conversion in presence of O2,H2O and SO2:Improvement of a Pt/Al2O3catalyst by Zr and Sn,and influence of the reducer C3H6or C3H8[J].Catal Commun,2008,9(5):664-669.
[10]GOULA M A,CHARISIOU N D,PAPAGERIDIS K N,DELIMITIS A,PAPISTA E,PACKATOURIDOU E,ILIOPOULOU E F,M ARNELLOS G,KONSOLAKIS M,YENTEKIS I V.A comparative study of the H2-assisted selective catalytic reduction of nitric oxide by propene over noble metal(Pt,Pd,Ir)/γ-Al2O3catalysts[J].J Environ Chem Eng,2016,4(2):1629-1641.
[11]MORE P M,NGUYEN D L,DONARE M K,UMBARKAR S B,GRANGER P,DUJARDIN C.Activation by pretreatment of Ag-Au/Al2O3bimetallic catalyst to improve low temperature HC-SCR of NOxfor lean burn engine exhaust[J].Appl Catal B:Environ,2015,174:145-156.
[12]MORE P M,NGUYEN D L,DONGARE M K,UMBARKAR S B,NUNS N,GIRARDON J S,DUJARDIN C,LANCELOT C,M AM EDE A S,GRANGER P.Rational preparation of Ag and Au bimetallic catalysts for the hydrocarbon-SCR of NOx:Sequential deposition vs.coprecipitation method[J].Appl Catal B:Environ,2015,162:11-20.
[13]MORE P M,JAGTAP N,KULAL A B,DONGARE M K,UMBARKER S B.Magnesia doped Ag/Al2O3-Sulfur tolerant catalyst for low temperature HC-SCR of NOx[J].Appl Catal B:Environ,2014,144:408-415.
[14]周皞,廖文裕,苏亚欣,林辛越.H2O和SO2对甲烷在金属铁表面还原NO的影响[J].洁净煤技术,2015,21(2):51-55.(ZHOU Hao,LIAO Wen-yu,SU Ya-xin,LIN Xin-yue.Influence of H2O and SO2on NO reduction by methane on the surface of iron[J].Clean Coal Technol,2015,21(2):51-55.)
[15]ZHOU H,SU Y X,LIAO W Y,ZHONG F C.NO reduction by propane over monolithic cordierite-based Fe/Al2O3catalyst:Reaction mechanism and effect of H2O/SO2[J].Fuel,2016,182:352-360.
[16]ZHOU H,SU Y X,LIAO W Y,ZHONG F C.Preparation,characterization,and properties of monolithic Fe/Al2O3/cordierite catalysts for NO reduction w ith C2H6[J].Appl Catal A:Gen,2015,505:402-409.
[17]KYRIIENKO P,POPOVYCH N,SOLOVIEV S,ORLYK S,DZWIGAJ S.Remarkable Activity of Ag/Al2O3/cordierite catalysts in SCR of NO w ith ethanol and butanol[J].Appl Catal B:Environ,2013,140/141(2):691-699.
[18]苏亚欣,任立铭,苏阿龙,邓文义.甲烷在金属铁及氧化铁表面还原NO的研究[J].燃料化学学报,2013,41(11):1393-1400.(SU Ya-xin,REN Li-ming,SU A-long,DENG Wen-yi.NO reduction by methane on the surface of iron oxides[J].J Fuel Chem Technol,2013,41(11):1393-1400.)
[19]苏亚欣,陆哲惺,周皞,窦逸峰,邓文义.丙烷在金属铁表面还原NO的实验研究[J].燃料化学学报,2014,42(12):1470-1477.(SU Ya-xin,LU Zhe-xing,ZHOU Hao,DOU Yi-feng,DENG Wen-yi.Experimental study on NO reduction by propane over iron[J].J Fuel Chem Technol,2014,42(12):1470-1477.)
[20]窦逸峰,苏亚欣,陆哲惺,周皞,邓文义.乙烷在金属铁表面还原NO的实验研究[J].燃料化学学报,2015,42(10):1273-1280.(DOU Yi-feng,SU Ya-xin,LU Zhe-xing,ZHOU Hao,DENG Wen-yi.Experimental study of NO reduction by ethane over iron[J].J Fuel Chem Technol,2015,42(10):1273-1280.)
[21]ZHOU H,LI K K,ZHAO B T,DENG W Y,SU Y X,ZHONG F C.Surface properties and reactivity of Fe/Al2O3/cordierite catalysts for NO reduction by C2H6:Effects of calcination temperature[J].Chem Eng J,2017,326:737-744.
[22]PUJILAKSONO B,JONSSON T,HALVARSSON M,SVENSSON J E,JOHANSSON L G.Oxidation of iron at 400-600℃in dry and wet O[J].Corros Sci,2010,52(5):1560-1569.
[23]SU J H,LIU Q Y,LIU Z Y,HUANG Z G.Honeycomb Cu O/Al2O3/cordierite catalyst for selective catalytic reduction of NO by NH3-Effect of Al2O3coating[J].Ind Eng Chem Res,2008,47(13):4295-4301.
[24]KYRIIENKO P,POPOVYCH N,SOLOVIEV S,ORLYK S,DZWIGAJ S.Remarkable Activity of Ag/Al2O3/cordierite catalysts in SCR of NO w ith ethanol and butanol[J].Appl Catal B:Environ,2013,140-141(2):691-699.
[25]KUL'KO E V,IVANOVA A S,LITVAK G S,KRYUKOVA G N,TSYBULYA S V.Preparation and microstruc-tural and textural characterization of single-phase aluminum oxides[J].Kinet Catal,2004,45(5):714-721.
[26]KOUOTOU P M,TIAN Z Y,VIEKER H,BEYER A,GLZHUSER A,KOHSEHINGHAUS K.Selective Synthesis ofα-Fe2O3thin films and effect of the deposition temperature and lattice oxygen on the catalytic combustion of propene[J].J M ater Chem A,2013,1(35):10495-10504.
[27]GONZLEZ-VELASCO J R,FERRET R,LPEZ-FONSECA R,GUTIRREZ-ORTIZ M A.Influence of particle size distribution of precursor oxides on the synthesis of cordierite by solid-state reaction[J].Pow der Technol,2005,153(1):34-42.
[28]POPOVICH N A,KIRIIENKO P I,SOLOV’EV S A,ORLIK S N,DZWIGAJ S.Role of active components of an Ag/Al2O3/cordierite catalyst in selective reduction of NO by ethanol[J].Theor Exp Chem,2012,48(4):258-264.
[29]SATOSHI S,MIKA S,MASATAKA F.Enhancing effect of water vapor on the reduction of lean NOx by ethanol over an Ag/Al2O3catalyst supported on cordierite honeycomb[J].React Kinet Catal Lett,1998,64(2):239-246.
[30]ZHANG R,KALIAGUINE S.Lean reduction of NO by C3H6over Ag/alumina derived from Al2O3,Al OOH and Al(OH)3[J].Appl Catal B:Environ,2008,78(3/4):275-287.
[31]RIEDEL T,CLAEYS M,SCHULZ H,SCHAUB G,NAM S S,JUN K W,CHOI M J,KISHAN G,LEE K W.Comparative study of Fischer-Tropsch synthesis w ith H2/CO and H2/CO2syngas using Fe-and Co-based catalysts[J].Appl Catal A:Gen,1999,186(1/2):201-213.
[32]LI J H,ZHU Y Q,RUI K,HAO J M.Improvement of catalytic activity and sulfur-resistance of Ag/Ti O2-Al2O3for NO reduction w ith propene under lean burn conditions[J].Appl Catal B:Environ,2008,80(3):202-213.
[33]WILLIAMS M F,FONFB,SIEVERS C.Hydrogenation of tetralin on silica-alumina-supported Pt catalysts I.Physicochemical characterization of the catalytic materials[J].J Catal,2012,251(2):485-496.