富氢气体可调控煤热解产物组成，深入认识这一过程中产物的调控机制可有效促进工艺的优化及其产业化。笔者以淖毛湖固定床反应装置在N2，H2和CH4气氛下，不同温度条件进行煤热解实验，通过对比煤热解反应气氛和温度对焦油产率、焦油的馏分分布和焦油的组成的影响，充分认识CH4气氛对煤中低温热解阶段(400~700 ℃)焦油产物的影响。结果表明:当煤热解温度高于600 ℃时，CH4气氛可提高煤热解的焦油产率。在600 ℃时，CH4气氛下焦油产率略高于N2气氛下的焦油产率。在650 ℃时，CH4气氛下焦油产率明显高于N2气氛下的焦油产率，低于H2气氛下的焦油产率。模拟蒸馏结果表明煤热解过程中，轻油和萘油的生成集中在450 ℃以下，洗油和沥青的生成集中在600 ℃以下，酚油和蒽油的生成分别集中在500和550 ℃以下。当温度高于600 ℃时，CH4气氛有利于蒽油的生成;当温度高于650 ℃时，CH4气氛有利于焦油中各个馏分的生成，其中轻油和酚油馏分的提高最为显著，轻油的含量高于H2气氛下轻油的含量，而酚油的含量与H2气氛下酚油的含量基本相同。GC/MS结果表明煤热解过程中，脂肪烃、烯烃、脂类和醇类化合物的生成主要集中在450 ℃以下，芳烃和酚类化合物的生成主要集中在600 ℃以下。当温度高于600 ℃时，CH4气氛有利于酚类和醇类化合物生成;当温度高于650 ℃时，CH4气氛有利于脂肪烃、芳烃、烯烃、酯类和醇类化合物的生成，其中酚类化合物的含量提高最为显著，但稍低于H2气氛下酚类化合物的含量。当温度高于600 ℃时，CH4可以为煤热解自由基提供氢和CHx自由基，参与到煤热解自由基的稳定和初级挥发分的二次反应。

The composition of coal pyrolysis products can be regulated by hydrogen-rich atmosphere.Understanding regulatory mechanism of products can promote process optimization and industrialization.The coal pyrolysis experiments using Naomaohu coal as coal sample were performed in a fixed bed reactor in N2,H2 and CH4 atmospheres.In this paper,tar yield,the contents of each fraction and composition in tar from coal pyrolysis at different reaction temperatures and atmospheres were compared to understand the role of CH4 in coal pyrolysis at low-medium pyrolysis temperature (400~700 ℃).The results show that the tar yield of coal pyrolysis is enhanced in CH4 atmosphere above 600 ℃.The tar yield in CH4 atmosphere is slightly higher than that in N2 atmosphere at 600 ℃.The tar yield in CH4 atmosphere is significantly higher than that in N2 atmosphere at 650 ℃,and lower than that in H2 atmosphere.The simulated distillation results show that light oil and naphthalene oil are mainly produced below 450 ℃ during coal pyrolysis,the formation temperatures of wash oil and asphaltene are mainly concentrated below 600 ℃,and the formation temperatures of phenol oil and anthracene oil are concentrated below 500 ℃ and 550 ℃,respectively.The content of anthracene oil in tar is enhanced in CH4 atmosphere above 600 ℃.When the temperature is higher than 650 ℃,the CH4 is conducive to the formation of each fraction in tar,of which light oil and phenol oil are greatly increased.The content of light oil is higher than that in H2 atmosphere,and the content of phenol oil is basically the same as that in H2 atmosphere.The GC/MS results show that the formation temperatures of aliphatic hydrocarbons,olefins,ester and alcohol compounds are mainly concentrated below 450 ℃ during coal pyrolysis,and the formation temperatures of aromatics and phenolic compounds are concentrated below 600 ℃.The contents of phenolic and alcohol compounds in tar are enhanced in CH4 atmosphere above 600 ℃.The contents of aliphatic hydrocarbons,aromatics,olefins,ester,and alcohol compounds in tar are enhanced in CH4 atmosphere above 650 ℃.The content of phenolic compounds is greatly increased,which is slightly lower than that in H2 atmosphere.The CH4 can provide·H and·CHx for coal pyrolysis to participate the stability of coal pyrolysis free radicals and the secondary reaction of primary volatiles,when the temperature is higher than 600 ℃.