乙炔为还原剂在Ce基催化剂上选择催化还原NO_2cx_的分析

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1、徐岩：乙炔为还原剂在ce基催化荆上选抒催化还原Nq的研究Theresearchfoundthat02competedwithNOforreductantinC2H2·SCRbuttheC2H2一SCRreactioncouldnotprogresswithout02．Ontheotherhand，C2H2couldnotbeoxidizedintheabsenceofNO．Therefore．wesuggestedthattheoxidizationofNOtoN02inC2H2-SCRistherate—determ

2、inedstep．Thisreactionmechanismisinconsistentwiththatofusingotherreductantsoverzeolitescatalystsintheliteratures．1kperformanceofCe-H-ZSM-5(si／A1=25)inapplicationwasinvestigated．Ce-H-ZSM-5fSi／A]=25)Wastreatedatthehightemperatureof650oCfor1hinthereactionfeed．andthe

3、behaviorofthecatalystdidnotchangeat325oC．Therefore，besidesthehighselectivity，Ce-H．ZSM一5(Si／AI=25)exhibitedgoodstabilityandresistanceofthermalimpact．11_1eactivitylossofcatalystcausedbyvapor(6．8％)inde-NOxreactionisreversible．Theactivityincreasingisbenefitfromthepr

4、esenceofS02(50ppm)underthedrycondition，whiledecreasingseriouslyunderthewetcondition．UsingofCI-L,andC3H6髂reducingagentcontainingthesamcaraountofCasC2H2OVerCe—H-ZSM-5(Si／Al=25)inSCRofNO，theconversionsofNOtoN2were0andl7％respectivelyat300oC、27％and29％respectivelyathi

5、ghtemperatureof500oC．TheresultsfurtherprovethepromisingadvantageofC2H2inapplicationcontrastwithCI-14andC3H6asreductantinSCRofNOx．KeyWords：Acetylene；NOx；Ce；SCR．川．火连理1：大学硕士学位论文插图或附表清单图1．1我国和欧、荚的排放标准的发展过程【7】⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯3图1．2CH4为还原齐0在不同含水量的条件下NO转化率随温度的变化⋯⋯⋯⋯⋯⋯．

6、1l图2．1C2H2．SCR反应装最图⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯25图3．1Ce．H-zeolites催化剂上C2H2．SCR活性⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯一27图3．2H．zeolites催化剂上C2H2．SCR活性⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯28图3．3QH2吸附⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．29圈3．4不同催化剂上NO的氧化性比较⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．30图3．5Ce-H-ZSM-5(25)催化剂上有无NO存在时C2H2转化的

7、比较⋯⋯⋯⋯⋯⋯⋯⋯．30图3．6不同硅铝比的Ce-H-zeolites催化剂上C2H2．SCR活性⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯33图3．7不同氧气浓度下Ce-H-ZSM一5(25)上C2H2．SCR的括性⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯一34网3．8空速对C2H2．SCR反应的影响⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯35圈3．9催化剂的稳定性一寿命实验⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯36图3．10催化剂的稳定性一热冲击实验⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．36圈3．1lCe—H—ZSM-5(25)催化剂I二S

8、02和H20对C2H2一SCR影响⋯⋯⋯⋯⋯．⋯⋯⋯⋯37图3．12S02的影响⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯～38图3．13Ce／H-ZSM-5催化荆在C2H2．SCR上的活性⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．41图3．14Ce纂H．zSM．5催化剂上的uv可见漫反射光谱⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯．．42网