N_2热解气氛中煤种对C元素迁移规律的影响

Effect of coal rank on carbon migration law in N_2 atmosphere

为提供煤炭地下气化物料平衡模型气化阶段中参与反应的碳量的计算方法,对大雁褐煤、协庄烟煤和昔阳无烟煤在N2气氛中进行慢速热解实验,研究了煤种对C元素迁移规律的影响。结果表明,热解过程中C元素迁移规律与煤的变质程度有关,对于无烟煤,原煤中的C元素向气化阶段的纯碳中的迁移比例a（C,气化纯碳）远远大于褐煤和烟煤,保持在93.19%左右,后者均为78%,而C元素向其他热解产物的迁移比例均在0%～1%之间;对于褐煤和烟煤,a（C,焦油）在600℃时均达到最大,分别为10.36%和14.53%;烟煤中a（C,CH4）和a（C,C2H4）均大于褐煤,与原煤挥发分含量有关;褐煤中a（C,CO）和a（C,CO2）均大于烟煤,与原煤含氧量有关;烟煤中N和S的赋存稳定性较高,使烟煤中a（C,COS）小于褐煤,而且烟煤中a（C,HCN）增长速率逐渐减小。

The slow pyrolysis experiments of Dayan lignite,Xiezhuang bituminous coal and Xiyang anthracite are carried out in N2 atmosphere,to study the effect of coal ranks on carbon migration law,which is helpful to calculate the quantity of carbon reacting at the gasification phase in mass balance model of UCG. The results show that： in the pyrolysis process,the carbon migration law is related to coal rank,a（ C, gasification carbon） is the carbon content ratio of gasification carbon to raw coal,and the average of a（ C,gasification carbon） for anthracite is 93. 19%,greater than that of lignite and bituminous coal,which is both 78%,but the carbon content ratio for other pyrolysis productions is very little and the range is between 0 and 1%; for lignite and bituminous coal the maximum of a（ C, tar） is 10. 36% and 14. 53% at600℃; a（ C,CH4） and a（ C,C2H4） are related to volatiles content in raw coal,for bituminous coal they are greater than lignite; a（ C,CO） and a（ C,CO2） are related to oxygen content in raw coal,for lignite they are greater than bituminous coal; the nitrogen and sulfur element exists inactively in the bituminous coal,so a（ C,COS） for bituminous coal is less than lignite,and the rising rate of a（ C,HCN） for bituminous coal decreases gradually.