摘要
利用两段固定床对三层床煤依次经过450℃低温、650℃中温和900℃高温的分级热解过程进行模拟实验,研究了上两段中低温和下两段中高温热解相邻两段之间的相互作用,揭示了多层床煤热解提高油气品质的机理。通过中低温热解的相互作用,焦油中轻质组分(沸点低于360℃的馏分)含量增加,热解气中CH_4含量增加,H_2含量减小,说明中低温热解主要通过半焦对热解产物的原位催化提质作用而提高焦油品质。通过中高温热解的相互作用,焦油收率和焦油中轻质组分含量增加,CH_4和CO含量升高,H_2含量下降,表示中高温热解的主要作用是在富含H_2气氛下热解提高焦油收率和品质.实验结果表明,多层床煤热解主要通过半焦的原位催化提质和富H_2气氛的协同作用而提高热解油气品质.
A two-stage fixed bed reactor was used to simulate the three-stage bed pyrolysis of coal for implementing the pyrolysis successively at low,medium and high temperatures of 450 ℃,650 ℃ and 900 ℃.The interaction of pyrolysis reactions between two adjacent stages,i.e.between the low-and medium-temperature pyrolysis in the upper two stages and between the medium-and high-temperature pyrolysis in the lower two stages,was investigated to reveal the mechanism of improvement on the quality of tar and gas for multi-stage bed pyrolysis of coal.It was found that the interaction between the low-and medium-temperature pyrolysis increased the light fractions in tar （boiling points below 360 ℃） and CH4 content in gas,while it decreased the H2 content in the gas.This indicates that the tar quality improvement via the interaction between the low-and medium-temperature pyrolysis in the upper two stages is mainly due to the in-situ upgrading of tar catalyzed by char.The interaction between the medium-and high-temperature pyrolysis increased the tar yield and light tar fractions,while it elevated the CH4 and CO contents and decreased the H2 content in the pyrolysis gas.These show that it is the H2-rich atmosphere that improved the yield and quality of tar by the interaction between the medium-and high-temperature pyrolysis.As a consequence,the multi-stage bed coal pyrolysis realized mainly the in-situ upgrading of tar under catalysis of char and the H2-rich atmosphere of pyrolysis that can improve the quality of the pyrolysis oil and gas.
出处
《煤炭转化》
CAS
CSCD
北大核心
2014年第1期55-60,64,共7页
Coal Conversion
基金
国家重点基础研究发展计划(973计划)项目(2011CB201304)
国家国际科技合作专项项目(2013DFG60060)
国家自然科学基金委员会与神华集团有限公司联合资助项目(51174283)
关键词
两段固定床
多层床
煤热解
油气品质
two-stage fixed bed
multi-stage bed
coal pyrolysis
quality of oil and gas
