淖毛湖煤和脱碱木质素共热解挥发物组成分布规律

Distribution of volatile composition from co-pyrolysis of NMH coal and dealkaline lignin

利用固定床反应器开展了淖毛湖煤和脱碱木质素的共热解实验,并研究了共热解产物的组成和产率变化规律。研究结果表明,共热解会降低半焦产率,促进热解气产率的提升,热解气产率最大提升了33.1%,共热解对于CH_4、CO的生成有明显的促进作用;在煤和木质素混合比例为1∶1时,煤和木质素的热解挥发分间交互作用表现最明显,热解焦油产率表现出正协同作用。在共热解过程中,愈创木酚向单酚、双酚转化,相较于理论计算值,单酚、双酚化合物的含量分别增加了2.9%和9.8%,而愈创木酚的含量降低了5.1%;其原因可能是羰基和羧基的断裂与挥发分间的交互作用增强,抑制了醚类、醛类、酸类化合物的生成,促进了酚类的生成、含氧气体的释放与热解焦油的稳定。木质素的引入,显著促进了煤热解焦油轻质化,焦油中轻质组分比例接近90%。

Experimental studies on co-pyrolysis of coal and lignin are carried out on a fixed-bed reactor to investigate composition and transformation of the co-pyrolysis products.The results show that co-pyrolysis reduces yield of char and promotes yield of gas,the maximum pyrolysis gas yield increases by 33.1%.Co-pyrolysis has a significant promotion effect on generation of CH4 and CO.The interaction between the pyrolyzed volatile fractions of coal and lignin shows the most pronounced interaction at a coal to lignin mixing ratio of 1∶1,and the pyrolysis tar yield shows a positive synergistic effect.Guaiacols are converted to monophenols and bisphenols during the co-pyrolysis process.Content of monophenols and bisphenols increase by 2.9%and 9.8%,respectively,while content of guaiacols decreases by 5.1%compared with the theoretically calculated values.The breakage of carbonyl and carboxyl groups,and the interaction with volatile components are enhanced,which inhibits formation of ethers,aldehydes and acids,and promotes generation of phenols,release of oxygenated gases and stabilization of pyrolysis tar.The introduction of lignin into coal pyrolysis also significantly promotes the upgrading of tar in which light components is nearly 90%.