淖毛湖煤慢速热解过程官能团相互作用

Interaction between functional groups during slow pyrolysis of Naomaohu coal

采用滴管炉,在短停留时间下,制备具有一定低温反应活性而消除主要低温交联位点的淖毛湖煤(NMHcoal)快速热解半焦(NRPchar),再将NMHcoal和NRPchar混合进行慢速热解,研究官能团间的相互作用。热重分析结果表明,NMHcoal/NRPchar混合比为5∶5,温度为500℃热解时具有较强的负协同作用。固定床热解结果表明,NMHcoal热解生成的挥发物部分扩散至NRPchar中,·CH_(3)与芳碳自由基以及·O有更多的结合概率与时间,使焦油中含甲基的萘、酚类增多,半焦中烷基化邻氧芳碳结构与醚类结构增加。析出的酚类增多,使半焦中连氧芳碳结构减少。NRPchar中生成较多的多环芳烃前体,它们与酚类物质发生反应生成多环芳烃和CO,使共热解焦油中5、6环化合物含量增加,而另一部分滞留在半焦中使其比表面积降低。

To study the interaction between functional groups during slow pyrolysis of coal,Naomaohu coal(NMHcoal)sample was pyrolyzed in a drop tube furnace reactor with a short residence time to prepare rapid pyrolysis char(NRPchar)with part remained reactivity of coal but most of the low-temperature crosslinking site precursor eliminated.TG results indicated that the pyrolysis of NMHcoal/NRPchar with a ratio of 5∶5 at 500℃ shows a strong negative synergy.The fixed bed pyrolysis results show that some volatiles generated by the pyrolysis of NMHcoal diffused into the NRPchar,which provided more probability and time to the combination of·CH_(3) with aromatic carbon radicals and·O.As a result,the structure of naphthalenes and phenols containing methyl groups in tar,and also the alkylated oxyaromatic carbon structure and ether structure in the char increased.The increased release of phenols reduced the oxyaromatic carbon structure in the char.More polycyclic aromatic hydrocarbon precursors are generated in NRPchar,they react with phenolic substances to generate polycyclic aromatic hydrocarbons and CO,which increase the content of 5 and 6 ring compounds in the co-pyrolysis tar,while the other part is retained in the semi-coke to reduce its specific surface area.