钨对高钒燃气脱硝催化剂的改性及SCR反应历程研究
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摘要
针对燃气工况特点,以高钒SCR脱硝催化剂为研究对象,采用共浸渍法添加钨进行改性,考察了V_2O_5-WO_3/Ti O_2催化剂的SCR脱硝活性,表征了WO_3掺杂对V_2O_5氧化还原能力和酸性位的影响,并研究了该类型催化剂的SCR反应历程。结果表明:对于高钒脱硝催化剂,WO_3掺杂可以显著拓宽催化剂在280～440℃内的活性区间,但无法大幅提高催化剂的最高脱硝效率。活性温度区间得以拓宽的主要原因是WO_3掺杂后与V_2O_5发生强相互作用,在TiO_2表面形成V—O—W物种并提高V~(5+)物种比例,从而增加表面Br■nsted酸和Lewis酸位。在SCR脱硝反应中,催化剂表面酸性位对NH_3的吸附和活化是反应决速步骤,其后与气相NO反应,由气相中O_2补缺催化剂活化NH_3过程中消耗的晶格氧或—OH氧。
According to the characteristics of gas turbine working conditions,the high vanadium SCR denitration catalyst was used as the research object,the addition of tungsten was modified by co-impregnation method,the SCR denitration activity of V_2O_5-WO_3/TiO_2 catalyst was investigated,the effect of WO_3 doping on V_2O_5 redox ability and acid site was characterized,and the SCR reaction process of this catalyst was researched. The results showed that in regard to high vanadium denitration catalysts,WO_3 doping could significantly broaden the activity range of the catalyst from 280 ℃ to 440 ℃,but it couldn' t improve the maximum denitrification activity of the catalyst by a wide margin. The main reason for the broadening of the active temperature range was that the strong interaction with V_2O_5 after WO_3 doping formed V—O—W species on the surface of TiO_2 and increased the proportion of V~(5+) species,thereby increasing the surface Br■nsted and Lewis acid sites. In the SCR denitration reaction,the ability of the acid sites to adsorb and activate NH_3 on the surface of the catalyst was a reactiondetermining step,and then reacted with the gas phase NO,and the O_2 in the gas phase would fill the lattice oxygen or —OH oxygen of catalyst consumed in the process of activating NH_3.
According to the characteristics of gas turbine working conditions,the high vanadium SCR denitration catalyst was used as the research object,the addition of tungsten was modified by co-impregnation method,the SCR denitration activity of V_2O_5-WO_3/TiO_2 catalyst was investigated,the effect of WO_3 doping on V_2O_5 redox ability and acid site was characterized,and the SCR reaction process of this catalyst was researched. The results showed that in regard to high vanadium denitration catalysts,WO_3 doping could significantly broaden the activity range of the catalyst from 280 ℃ to 440 ℃,but it couldn' t improve the maximum denitrification activity of the catalyst by a wide margin. The main reason for the broadening of the active temperature range was that the strong interaction with V_2O_5 after WO_3 doping formed V—O—W species on the surface of TiO_2 and increased the proportion of V~(5+) species,thereby increasing the surface Br■nsted and Lewis acid sites. In the SCR denitration reaction,the ability of the acid sites to adsorb and activate NH_3 on the surface of the catalyst was a reactiondetermining step,and then reacted with the gas phase NO,and the O_2 in the gas phase would fill the lattice oxygen or —OH oxygen of catalyst consumed in the process of activating NH_3.
引文
[1]刘志坦,李玉刚,王凯.中国燃气电厂烟气排放现状及政策趋势[J].中国电力,2018,51(1):147-153.
[2]王飞.环保新形势下燃机脱硝技术选择[J].能源与环境,2015(1):75-77.
[3]江苏省燃气电厂环保现状调研[R].南京:国电环境保护研究院,2017.
[4]黄素华,苏保兴,华宇东,等.燃气轮机NOx排放控制技术[J].中国电力,2012,45(6):100-103.
[5]王五清,王旭,贺元启.燃气电厂脱硝技术方案的选择与分析[J].华北电力技术,2013(4):38-41.
[6] Busca G,Lietti L,Ramis G,et al. Chemical and mechanistic aspects of the selective catalytic reduction of NOx,by ammonia over oxide catalysts:A review[J]. Applied Catalysis B Environmental,1998,18(1/2):1-36.
[7] Dumesic J A,Topse N Y,Slabiak T,et al. Microiunetic analysis of the selective catalytic reduction(SCR)of nitric oxide over vanadia/titania-based catalysts[J]. Studies in Surface Science&Catalysis,1993,75:1325-1337.
[8] Dumesic J A,Topse N Y,Topse H. Kinetics of selective catalytic reduction of nitric oxide by ammonia over vanadia/titania[J].Journal of Catalysis,1996,163(2):409-417.
[9] Takagi M,Kawai T,Soma M,et al. The mechanism of the reaction between NOx,and NH3,on V2O5,in the presence of oxygen[J].Journal of Catalysis,1977,50(3):441-446.
[10] Zhang S,Zhong Q. Surface characterization studies on the interaction of V2O5-WO3/Ti O2,catalyst for low temperature SCR of NO with NH3[J]. Journal of Solid State Chemistry,2015,221:49-56.
[11]吴碧君,刘晓勤,肖萍,等. Mn-Fe/Ti O2低温NH3选择性还原NO催化活性及其反应机制[J].中国电机工程学报,2007,27(17):51-56.
[12]吴碧君,肖萍,刘晓勤. MnOx-WO3/Ti O2NH3选择性还原NOx的催化性能与动力学[J].化工学报,2011,62(4):940-946.
[13] Alemany L J,Berti F,Ramis G,et al. Characterization and composition of commercial V2O5-WO3/Ti O2SCR catalysts[J].Applied Catalysis B:Environmental,1996,10(4):299-311.
[14] Cheng K,Liu J,Zhao Z,et al. Direct synthesis of V-W-Ti nanoparticle catalysts for selective catalytic reduction of NO with NH3[J]. Rsc advances,2015,5(56):45172-45183.
[15] Chen J,Yang R. Role of WO3in mixed V2O5-WO3/Ti O2catalysts for selective catalytic reduction of nitric oxide with ammonia[J].Applied Catalysis A:General,1992,80(1):135-148.
[16]廷亮,武旭增,刘庆.新型HS-2钒催化剂本征活性评价[J].河南化工,1993(10):24-27.
[17] Nicosia D,Czekaj I,Krcher O. Chemical deactivation of V2O5-WO3/Ti O2SCR catalysts by additives and impurities from fuels,lubrication oils and urea solution[J]. Applied Catalysis B:Environmental,2008,77(3/4):228-236.
[18] Amiridis M D,Duevel R V,Wachs I E. The effect of metal oxide additives on the activity of V2O5/Ti O2,catalysts for the selective catalytic reduction of nitric oxide by ammonia[J]. Applied Catalysis B:Environmental,1999,20(2):111-122.
[19] Schobing J,Tschamber V,Brilhac J F,et al. Simultaneous soot combustion and NOx,reduction over a vanadia-based selective catalytic reduction catalyst[J]. Comptes Rendus Chimie,2017.
[20] Yu W,Wu X,Si Z,et al. Influences of impregnation procedure on the SCR activity and alkali resistance of V2O5-WO3/Ti O2,catalyst[J]. Applied Surface Science,2013,283(20):209-214.
[21] Wang C,Yang S,Chang H,et al. Dispersion of tungsten oxide on SCR performance of V2O5-WO3/Ti O2:acidity,surface species and catalytic activity[J]. Chemical Engineering Journal,2013,225(6):520-527.
[22] Putluru S S R,Schill L,Godiksen A,et al. Promoted V2O5-WO3/Ti O2,catalysts for selective catalytic reduction of NO with NH3,at low temperatures[J]. Applied Catalysis B Environmental,2016,183:282-290.
[23] Lietti L,Nova I,Ramis G,et al. Characterization and reactivity of V2O5-WO3/Ti O2,De-NOx,SCR catalysts[J]. Journal of Catalysis,1999,187(2):419-435.
[24] Sun C,Dong L,Yu W,et al. Promotion effect of tungsten oxide on SCR of NO with NH3,for the V2O5-WO3/Ti0. 5Sn0. 5O2,catalyst:experiments combined with DFT calculations[J]. Journal of Molecular Catalysis A Chemical,2011,346(1):29-38.
[2]王飞.环保新形势下燃机脱硝技术选择[J].能源与环境,2015(1):75-77.
[3]江苏省燃气电厂环保现状调研[R].南京:国电环境保护研究院,2017.
[4]黄素华,苏保兴,华宇东,等.燃气轮机NOx排放控制技术[J].中国电力,2012,45(6):100-103.
[5]王五清,王旭,贺元启.燃气电厂脱硝技术方案的选择与分析[J].华北电力技术,2013(4):38-41.
[6] Busca G,Lietti L,Ramis G,et al. Chemical and mechanistic aspects of the selective catalytic reduction of NOx,by ammonia over oxide catalysts:A review[J]. Applied Catalysis B Environmental,1998,18(1/2):1-36.
[7] Dumesic J A,Topse N Y,Slabiak T,et al. Microiunetic analysis of the selective catalytic reduction(SCR)of nitric oxide over vanadia/titania-based catalysts[J]. Studies in Surface Science&Catalysis,1993,75:1325-1337.
[8] Dumesic J A,Topse N Y,Topse H. Kinetics of selective catalytic reduction of nitric oxide by ammonia over vanadia/titania[J].Journal of Catalysis,1996,163(2):409-417.
[9] Takagi M,Kawai T,Soma M,et al. The mechanism of the reaction between NOx,and NH3,on V2O5,in the presence of oxygen[J].Journal of Catalysis,1977,50(3):441-446.
[10] Zhang S,Zhong Q. Surface characterization studies on the interaction of V2O5-WO3/Ti O2,catalyst for low temperature SCR of NO with NH3[J]. Journal of Solid State Chemistry,2015,221:49-56.
[11]吴碧君,刘晓勤,肖萍,等. Mn-Fe/Ti O2低温NH3选择性还原NO催化活性及其反应机制[J].中国电机工程学报,2007,27(17):51-56.
[12]吴碧君,肖萍,刘晓勤. MnOx-WO3/Ti O2NH3选择性还原NOx的催化性能与动力学[J].化工学报,2011,62(4):940-946.
[13] Alemany L J,Berti F,Ramis G,et al. Characterization and composition of commercial V2O5-WO3/Ti O2SCR catalysts[J].Applied Catalysis B:Environmental,1996,10(4):299-311.
[14] Cheng K,Liu J,Zhao Z,et al. Direct synthesis of V-W-Ti nanoparticle catalysts for selective catalytic reduction of NO with NH3[J]. Rsc advances,2015,5(56):45172-45183.
[15] Chen J,Yang R. Role of WO3in mixed V2O5-WO3/Ti O2catalysts for selective catalytic reduction of nitric oxide with ammonia[J].Applied Catalysis A:General,1992,80(1):135-148.
[16]廷亮,武旭增,刘庆.新型HS-2钒催化剂本征活性评价[J].河南化工,1993(10):24-27.
[17] Nicosia D,Czekaj I,Krcher O. Chemical deactivation of V2O5-WO3/Ti O2SCR catalysts by additives and impurities from fuels,lubrication oils and urea solution[J]. Applied Catalysis B:Environmental,2008,77(3/4):228-236.
[18] Amiridis M D,Duevel R V,Wachs I E. The effect of metal oxide additives on the activity of V2O5/Ti O2,catalysts for the selective catalytic reduction of nitric oxide by ammonia[J]. Applied Catalysis B:Environmental,1999,20(2):111-122.
[19] Schobing J,Tschamber V,Brilhac J F,et al. Simultaneous soot combustion and NOx,reduction over a vanadia-based selective catalytic reduction catalyst[J]. Comptes Rendus Chimie,2017.
[20] Yu W,Wu X,Si Z,et al. Influences of impregnation procedure on the SCR activity and alkali resistance of V2O5-WO3/Ti O2,catalyst[J]. Applied Surface Science,2013,283(20):209-214.
[21] Wang C,Yang S,Chang H,et al. Dispersion of tungsten oxide on SCR performance of V2O5-WO3/Ti O2:acidity,surface species and catalytic activity[J]. Chemical Engineering Journal,2013,225(6):520-527.
[22] Putluru S S R,Schill L,Godiksen A,et al. Promoted V2O5-WO3/Ti O2,catalysts for selective catalytic reduction of NO with NH3,at low temperatures[J]. Applied Catalysis B Environmental,2016,183:282-290.
[23] Lietti L,Nova I,Ramis G,et al. Characterization and reactivity of V2O5-WO3/Ti O2,De-NOx,SCR catalysts[J]. Journal of Catalysis,1999,187(2):419-435.
[24] Sun C,Dong L,Yu W,et al. Promotion effect of tungsten oxide on SCR of NO with NH3,for the V2O5-WO3/Ti0. 5Sn0. 5O2,catalyst:experiments combined with DFT calculations[J]. Journal of Molecular Catalysis A Chemical,2011,346(1):29-38.