摘要
以陕西低阶烟煤为原料,研究了在低碱煤质量比(mKOH∶mcoal=1∶1)下,不同温度时浸渍法、超声法和干混法三种KOH添加方式对煤热解活化过程中气相产物CH4,CO和CO2释放规律及固相产物中活性炭和碳纳米管混合物的影响。结果表明:浸渍法中KOH通过扩散作用进入煤颗粒内部孔隙,KOH充分分散与煤接触良好,活化反应剧烈,所制备固相产物的比表面积为1081.31 m^2/g(40℃),远大于超声法制备的固相产物的比表面积(880.39 m^2/g)和干混法制备的固相产物的比表面积(425.66 m^2/g);气相产物中CO和CO2累积量由大到小的KOH添加方式依次为浸渍法、超声法、干混法,CH4累积量由大到小的KOH添加方式依次为干混法、超声法、浸渍法;KOH在活化煤过程中,使煤中固有Fe等矿物元素暴露出来,二者共同催化煤热解过程中产生的CH4等烃类气体转化为碳纳米管,固相产物碳纳米管的表观含量由大到小的KOH添加方式依次为浸渍法、超声法、干混法。
Using the low-rank bituminous coal from Shaanxi province as the raw material,the samples were prepared with threedifferent KOH adding methods,including the precursor-based impregnation method at different temperatures,the ultrasonic method and the dry mixing method.The release of CH4,CO,CO2 and the mixture of activated carbon and carbon nanotubes in the solid-phase products during the coal pyrolysis and activation processes were studied under the low KOH/coal ratio(mKOH∶mcoal=1∶1).The results show that when the impregnation method is used,KOH enters into the internal pores of coal particles through diffusion,and KOH is fully dispersed and well connected with the coal,which leads to the active reaction.The specific surface area of the prepared solid product is 1081.31 m^2/g(40℃),much higher than that obtained by using the ultrasonic(880.39 m^2/g)and dry mixing methods(425.66 m^2/g).The impregnation method leads to the highest cumulative amount of CO and CO2 in the gas-phase product,followed by the ultrasonic methodand then the dry mixing method,while the ultrasonic method leads to the highest cumulative amount of CH4 and followed by the ultrasonic method.During the activation of coal,KOH makes the inherent mineralssuch as Fe accessible,which catalyzes the conversion of the hydrocarbon gases during the coal pyrolysis into carbon nanotubes.And the impregnation method produces the maximum apparent content of carbon nanotubes,followed by the ultrasonic method,and the dry mix method leads to the least apparent content of carbon nanotubes.
作者
罗云焕
张天开
吕学枚
张永发
王影
刘俊
LUO Yunhuan;ZHANG Tiankai;LYU Xuemei;ZHANG Yongfa;WANG Ying;LIU Jun(Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, 030024 Taiyuan, China;College of Chemistry and Chemical Engineering, Taiyuan University of Technology, 030024 Taiyuan, China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2020年第5期18-26,共9页
Coal Conversion
关键词
煤基活性炭
KOH活化
低碱法
碳纳米管
煤中矿物质元素
coal-based activated carbon
KOH activation
low KOH/coal mass ratio
carbon nanotubes
mineral elements in coal
