煤热解过程中焦炭氮变化规律的试验研究  

Experimental Investigation on Char Nitrogen Conversion During Coal Pyrolysis

作　　者：闫晓[1] 车得福[1] 徐通模[1] 

机构地区：[1]西安交通大学能源与动力工程学院

出　　处：《西安交通大学学报》2004年第9期980-984,共5页Journal of Xi'an Jiaotong University

基　　金：国家重点基础研究专项经费资助项目 (G1 9990 2 2 2 1 0 );教育部高等学校博士学科点专项科研基金资助项目 (RFDP2 0 0 2 0 6980 48)

摘　　要：为研究煤中氮在燃烧第一阶段随挥发分析出进入均相反应与残留煤焦发生异相反应的比例,评估均相反应与异相反应对最终氮氧化物排放贡献的大小提供依据,建立了固定床反应系统并在低加热速率条件下研究了煤阶、温度、脱灰以及不同灰成分在热解过程中对焦炭氮转化率变化规律的影响.研究发现:当高阶煤热解时,氮更多地保留在煤焦中,而低阶煤中的氮则容易析出形成气态含氮产物;高温利于氮从煤焦中析出;脱灰对低阶煤中氮的析出有强烈的抑制作用,脱灰对高阶煤的影响不如低阶煤明显;煤中含Ti、Na、K、Fe和Ca等类矿物质在温度高于800℃时促进氮从煤焦中析出,Mg的存在使焦炭氮的转化率略有提高,Si和Al类矿物质对于氮的析出无明显作用.Char nitrogen conversion during coal pyrolysis was studied in a fixed bed quartz reactor with a slow heating rate. Eleven coals with carbon contents of 77%-93% (daf) and corresponding demineralized samples were used to examine rank and demineralization dependence of nitrogen distribution between char and volatile. Furthermore, Fushun parent coal sample, demineralized and catalysts added samples were pyrolyzed in the reactor to investigate the effect of different minerals species on nitrogen emission during pyrolysis at 400-1300°C. The results show that larger nitrogen retention can be found in the chars derived from a higher rank coal. The char nitrogen increases with increased C (daf) and reaches a maximum at=90%C (daf) at the temperatures lower than 1000°C. At 1200°C the char-N increases monotonically with increased rank. Char nitrogen conversion is almost inversely proportional to pyrolysis temperature in despite of coal rank, otherwise demineralization drastically suppresses nitrogen emission from char during pyrolysis. Ti, Na, K, Fe, and Ca additions remarkably decrease char nitrogen at temperatures higher than 800°C, whereas the presence of Mg reduces the volatile nitrogen slightly. Si and Al are inert species in inherent minerals of coal.

关 键 词：煤 热解 氮 焦炭氮转化率 

分 类 号：X131.1[环境科学与工程—环境科学]