CAJ | 학술논문

采用程序控温电加热水平陶瓷管反应器，在N2气氛和模拟烟气气氛中、300～1100℃下，研究了水蒸气对甲烷在金属铁表面还原NO行为的影响，并对反应前、后铁样品进行了X光衍射（ XRD）、扫描电子显微镜（ SEM）及X光电子能谱（ XPS）等表征。结果表明，水蒸气对甲烷在金属铁表面还原NO行为的影响较小。在N2气氛中，水蒸气参与了金属铁的氧化；与无水蒸气时相比，水蒸气存在时NO还原效率有所下降。当水蒸气含量从2．5％增加到7％时，由于水蒸气对金属铁的氧化导致其表面形成疏松的微观孔隙，使得NO的还原效率随水蒸气含量的增加而提高。甲烷则参与了铁氧化物的还原，使铁样品表面形成相对致密的Fe3 O4和FeO氧化层，不利于NO与金属铁的接触，使得NO的还原效率低于无甲烷时的结果。在模拟烟气条件下，水蒸气使得甲烷在金属铁表面还原NO的效率增加；在1050℃下，反应段过量空气系数SR 1＝0．7和燃尽段过量空气系数SR2＝1．2时，含7％的 H2 O和无H2 O条件下脱硝效率分别为96．7％和90．6％。而在湿烟气中SO2使NO还原效率略有下降。持久性脱硝实验结果表明，当反应温度为1050℃时，在含7％的H2 O、00．2％的SO2的模拟烟气中，1．14％的甲烷在金属铁表面持续50 h都能保持90％以上的脱硝效率。
채용정서공온전가열수평도자관반응기，재N2기분화모의연기기분중、300～1100℃하，연구료수증기대갑완재금속철표면환원NO행위적영향，병대반응전、후철양품진행료X광연사（ XRD）、소묘전자현미경（ SEM）급X광전자능보（ XPS）등표정。결과표명，수증기대갑완재금속철표면환원NO행위적영향교소。재N2기분중，수증기삼여료금속철적양화；여무수증기시상비，수증기존재시NO환원효솔유소하강。당수증기함량종2．5％증가도7％시，유우수증기대금속철적양화도치기표면형성소송적미관공극，사득NO적환원효솔수수증기함량적증가이제고。갑완칙삼여료철양화물적환원，사철양품표면형성상대치밀적Fe3 O4화FeO양화층，불리우NO여금속철적접촉，사득NO적환원효솔저우무갑완시적결과。재모의연기조건하，수증기사득갑완재금속철표면환원NO적효솔증가；재1050℃하，반응단과량공기계수SR 1＝0．7화연진단과량공기계수SR2＝1．2시，함7％적 H2 O화무H2 O조건하탈초효솔분별위96．7％화90．6％。이재습연기중SO2사NO환원효솔략유하강。지구성탈초실험결과표명，당반응온도위1050℃시，재함7％적H2 O、00．2％적SO2적모의연기중，1．14％적갑완재금속철표면지속50 h도능보지90％이상적탈초효솔。
The effect of water vapor on NO reduction by methane over iron was investigated at 300~1 100℃in an electrically heated ceramic tubular flow reactor in both N2 and simulated flue gas atmospheres.The iron samples before and after reaction were characterized by XRD, SEM and XPS.The results dem onstrated that water vapor has a small effect on NO redcu tion by methane over iron.In N2 atmosphere, water vapor isi nvolved in the oxdi ait on of iron; com parde with that in the asb ence of water vapor, the NO reud ction efficiencyi s decreased slightly when 2.5%~7%water vapor is added into the reaction stream.However, the NO reduction efficiency increases with the increase of water content from 2.5% to 7%, as water vapor may promote the oxidation of iron, of rming porous iron surface.Methane is in volev d in the reduction of the iron oxidse , leadni g to thef ormta ion of a dense layer of Fe3 O4 and FeO, which may inhabit the interaction of NO with metallic iron and then decrease the NO reduction efficiency, as compared with that without methane.In the simulated flue gas atmosphere, water vapor promotes the NO reduction yb methane over iron.When the excess air ratio is 0.7 in reaction zone (SR1) and 1.2 in burnout zone (SR2), the NO reduction efficiency at 1 050℃is 96.7%in the presence of 7%water vapor, compared with the value of 90.6% in the absence of water vapor.SO2 causes a slight decrease of NO reduction.Long term test results showed that over iron at 1 050℃in the simulated flue gas atmosphere containing 7% H2 O and 0.02% SO2 , NO reduction efficiency remains higher than 90% after reaction for 50 h in the presence of 1.14%methane.