Abstract: Low rank coal resources are abundant,and catalytic pyrolysis is an important way to realize clean and efficient utilization of low rank coal resources.At present,the low rank coal catalytic pyrolysis technology has some bottlenecks,such as low tar yield,high heavy components,and difficulty in recovering catalyst.Therefore,in this study,the magnetic core shell carrier HZSM-5@SiO2@Fe3O4(HSF)and the magnetic Mo/HSF catalyst for coal pyrolysis were designed and prepared.The influence of the layers number of SiO2 thermal insulation coating,heat treatment temperature and time,HZSM-5 carrier layer on HSF magnetism were studied.The catalytic activity and the recovery rate by the magnetic separation of Mo/HSF in coal pyrolysis were investigated by using Bulanta coal (BLCoal) as sample.The results show that under normal temperature conditions,with the increase of SiO2 coating layers,the SiO2@Fe3O4 saturation magnetization intensity and magnetic separation recovery are reduced to some different degrees.When the number of SiO2 coating layers is two,the saturation magnetization intensity and magnetic recovery rate decrease in the least degrees.The increase of heat treatment temperature or the extension of heat treatment time,and coating HZSM-5 carrier layer can result in the decrease of the recovery rate.The 5% Mo/HSF magnetic catalyst using two layers of SiO2@Fe3O4 as magnetic core has the best catalytic performance.Under the action of 5%Mo/HSF catalyst,the tar yield reaches 10.8%,the benzene content in the tar increases by 2.31%,phenolic content is almost unchanged,the aliphatic hydrocarbon content increases by 8.44%,the polycyclic aromatic hydrocarbon content decreases by 9.64%.The introduction of active component Mo can not only improve the tar quality,but also increase the ratio of methane to CO in the gas,the methane content in the gas reaches more than 50%.The recovery of Mo/HSF catalyst can reach 90.3% in the first magnetic separation.With the increase of recovery times of magnetic separation,the catalyst activity and recovery rate decrease obviously,which is mainly caused by the decrease of magnetic properties due to the carbon deposition on the surface of catalyst and the reduction of magnetic core.