Abstract In this paper, to investigate the catalytic pyrolysis behavior of coal (XJ) volatiles over two hematite (HA and HB), a double-layered fixed-bed reaction apparatus, which was easy to separate coal and catalysts was employed to measure the pyrolysis tar yield, and the composition of pyrolysis tar and gas was investigated by GC-MS and GC. The results indicated that both hematite A and hematite B reduced the tar yield and caused an increase in CH4, CO2 and H2 output. Analysis of the chemical composition of tar indicated that XJ had a high content of pitch (46.39 %). At the same time, the addition of HA and HB decreased the pitch content by 7.59 and 8.88 %, respectively. Then, the change in the hematite chemical composition and physical structure after catalytic pyrolysis was characterized by XRD, TEM, XPS, SEM and N2 adsorption-desorption. Furthermore, a catalytic mechanism was proposed to illustrate the transformation of pyrolysis tar over hematite. Fe atoms and lattice oxygen are the decisive factors in the bond cleavage of pyrolysis tar. Fe atoms can break the C C and C H bonds of aliphatic hydrocarbons, while lattice oxygen can promote C O bond cleavage and produce CO2.

中文翻译：

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赤铁矿催化热解煤挥发分制轻焦油的研究

摘要 为研究煤（XJ）挥发物在两种赤铁矿（HA和HB）上的催化热解行为，采用易于分离煤和催化剂的双层固定床反应装置测量热解过程。焦油产率，并通过GC-MS和GC研究了热解焦油和气体的组成。结果表明赤铁矿 A 和赤铁矿 B 都降低了焦油产量，并导致 CH4、CO2 和 H2 输出增加。焦油化学成分分析表明，XJ 的沥青含量较高（46.39%）。同时，HA和HB的加入使沥青含量分别降低了7.59%和8.88%。然后，通过XRD、TEM、XPS、SEM和N2吸附-解吸表征了催化热解后赤铁矿化学成分和物理结构的变化。此外，提出了一种催化机制来说明热解焦油在赤铁矿上的转化。Fe原子和晶格氧是热解焦油键断裂的决定性因素。Fe原子可以破坏脂肪烃的CC和CH键，而晶格氧可以促进CO键断裂并产生CO2。