ZnCl2 catalyst on the catalytic depolymerization of sub bituminous coal and its vitrinite rich concentrate

The effects of adding different contents of ZnCl 2 catalysts into sub bituminous coal on the catalytic depolymerization products of tar composition，gas phase composition and char were investigated by Gray King assay，gas chromatography analysis，and comprehensive two dimensional gas chromatography mass spectrometry (GC×GC MS) and its possible catalytic mechanism was discussed. The product distribution results showed that after the addition of the ZnCl 2 catalyst，the yield of char was reduced and the yield of tar was improved. When the addition amount of Zn was 0.10%，the promotion effect on the pyrolysis catalytic depolymerization was the highest，the tar yield increased to 13.83% compared with 12.05% of the raw coal. According to the results of tar components analysis，the content of polycyclic aromatic hydrocarbons in the tar increased the most. Gas phase composition analysis showed that the H 2 content increased significantly，while the CH 4 content decreased slightly，the C 2+ and other low carbon hydrocarbons decreased significantly，and the CO and CO 2 yields remained basically unchanged. It indicates that with the addition of the Zn based catalyst，free radicals were more inclined to generate large molecular tar with some large free radical fragments，rather than small molecular gases. Moreover，the catalytic depolymerization effect of the addition of 0.10% Zn based catalyst on the vitrinite rich concentrate obtained from the separation of the sub bituminous coal was investigated. The tar yield obtained from the depolymerization of the vitrinite rich concentrate reached 16.17%，which was an increase of 4.12% compared to the raw coal. Also the Zn catalyst addition could further increase the thermal depolymerization degree of vitrinite rich concentrate and further increase the tar yield to 17.87%.