化工学报
化工學報
화공학보
JOURNAL OF CHEMICAL INDUSY AND ENGINEERING (CHINA)
2014年
6期
2249-2255
,共7页
方晓晴%范垂钢%都林%宋文立%林伟刚%李松庚
方曉晴%範垂鋼%都林%宋文立%林偉剛%李鬆庚
방효청%범수강%도림%송문립%림위강%리송경
煤焦%氮氧化物%还原%选择性
煤焦%氮氧化物%還原%選擇性
매초%담양화물%환원%선택성
coal char%nitric oxide%reduction%selectivity
选用3种不同煤焦,采用程序升温和恒温实验方法,在固定床上考察了不同实验条件下的NO转化率和C对NO选择性,分析了煤焦脱硝的机理和影响因素。实验结果表明:NO和O2在煤焦表面发生化学吸附所形成的络合物在脱硝过程中起着关键作用,影响C-NO反应和C-O2反应的竞争与协作关系。在所考察的煤焦中锡林浩特褐煤焦脱硝效果最好,当温度为723 K时烟道气中NO还原率可达99%;在温度623~923 K、O2浓度0~5%范围内,提高温度和O2浓度均有利于提高NO转化率,而降低O2浓度有利于提高C对NO选择性;烟道气中NO浓度越高,其转化率越低,但C对NO选择性越高。
選用3種不同煤焦,採用程序升溫和恆溫實驗方法,在固定床上攷察瞭不同實驗條件下的NO轉化率和C對NO選擇性,分析瞭煤焦脫硝的機理和影響因素。實驗結果錶明:NO和O2在煤焦錶麵髮生化學吸附所形成的絡閤物在脫硝過程中起著關鍵作用,影響C-NO反應和C-O2反應的競爭與協作關繫。在所攷察的煤焦中錫林浩特褐煤焦脫硝效果最好,噹溫度為723 K時煙道氣中NO還原率可達99%;在溫度623~923 K、O2濃度0~5%範圍內,提高溫度和O2濃度均有利于提高NO轉化率,而降低O2濃度有利于提高C對NO選擇性;煙道氣中NO濃度越高,其轉化率越低,但C對NO選擇性越高。
선용3충불동매초,채용정서승온화항온실험방법,재고정상상고찰료불동실험조건하적NO전화솔화C대NO선택성,분석료매초탈초적궤리화영향인소。실험결과표명:NO화O2재매초표면발생화학흡부소형성적락합물재탈초과정중기착관건작용,영향C-NO반응화C-O2반응적경쟁여협작관계。재소고찰적매초중석림호특갈매초탈초효과최호,당온도위723 K시연도기중NO환원솔가체99%;재온도623~923 K、O2농도0~5%범위내,제고온도화O2농도균유리우제고NO전화솔,이강저O2농도유리우제고C대NO선택성;연도기중NO농도월고,기전화솔월저,단C대NO선택성월고。
NO reduction by coal char was investigated in a fixed bed reactor using a simulated flue gas. Two different operation modes(programmed temperature and constant temperature) were employed to explore the mechanism of NO removal by coal char and to study the effects of the variables on NO removal efficiency and selectivity including temperature, coal type, NO and oxygen concentrations in flue gas and space velocity. The results indicated that surface complexes formed by chemisorption of NO and O2 on carbon active sites played the key role in reactions between C-NO and C-O2. XLHT coal char showed both the highest rate of NO reduction and C-NO selectivity among the coal chars studied. NO reduction by XLHT coal char could reach 99% at 723 K. Under the experimental conditions in this work, an increase in temperature and/or oxygen concentration in flue gas enhanced NO reduction. However, C-NO selectivity decreased with the increasing O2 concentration. Higher NO concentration in flue gas led to lower NO reduction but higher C-NO selectivity.