Microwave-assisted catalytic pyrolysis is considered to be a promising technology for coal-staged conversion due to its high efficiency and selectivity. This work was undertaken to investigate the pyrolysis behavior and products quality of microwave-assisted pyrolysis of low rank coal catalyzed by metallic catalysts (K, Ca and Fe) with both dielectric response and catalytic effect via a microwave tube furnace. The mechanism of metallic catalysts on catalytic cracking tar under microwave radiation was also investigated. The dielectric properties and physicochemical structure of coal chars were characterized by a vector network analyzer, XRD, FT-IR, SEM, EDS, and Raman. The chemical structure characteristics of generated tars were determined by FT-IR and GC-MS. Results manifested that microwave interacted preferentially with metal catalysts by polarization and conductivity loss could efficiently induce the occurrence of catalytic pyrolysis reactions to generate high yield syngas (CO + H₂). Specifically, the dielectric loss factor of resultant chars was considerably improved with the introduction of metallic catalysts especial for Ca and Fe. Furthermore, it is found that metal catalysts dramatically enriched the amorphous carbon structure in produced chars whereas in favour of suppressing the trend of carbon graphitization. Additionally, the transformation of larger polycyclic aromatic compounds into lighter tar species was catalytically accelerated, resulting in the large proportion of single-ring aromatics in tar under the synergistic effect between microwave and metal catalysts.

微波辅助催化热解因其高效和高选择性而被认为是一种有前途的煤级转化技术。进行这项工作以研究微波催化热解行为和金属质量（K，Ca和Fe）催化的低级煤的微波辅助热解的介电响应和催化作用，通过微波管式炉。还研究了金属催化剂在微波辐射下催化裂化焦油的机理。通过矢量网络分析仪，XRD，FT-IR，SEM，EDS和拉曼表征了煤焦的介电性能和理化结构。通过FT-IR和GC-MS测定生成的焦油的化学结构特征。₂）。具体地，通过引入特别用于Ca和Fe的金属催化剂，显着提高了所得炭的介电损耗因子。此外，发现金属催化剂极大地丰富了所产生的炭中的无定形碳结构，同时有利于抑制碳石墨化的趋势。另外，在微波和金属催化剂之间的协同作用下，催化加速了较大的多环芳族化合物向较轻的焦油物质的转化，从而导致焦油中有很大比例的单环芳烃。