Macro maceral separation of low-rank coal and the pyrolysis behavior of the maceral-rich fractions

An ideal way of clean and efficient utilization of low-rank coal by separating it into different maceral-rich fractions and then choose the appropriate utilizing method based on its composition and structure was proposed. In this paper, the coal sample was successfully separated into vitrinite-enriched coal (VC), inertinite-enriched coal (IC) and mineral-enriched coal (MC) by macro maceral separation method, and the structure and pyrolysis characteristics of different maceral-rich fractions were studied. The results showed that, the less ordered carbon and the active components functional groups as the aliphatic hydrocarbons were significantly enriched in VC, thus the tar yield after pyrolysis was 15.68%, which increased by 4.37% compared with that of raw coal (11.31%), and more aliphatic hydrocarbons were enriched in the tar. The structure of aromatic ring, functional groups of stable components and the ordered carbons were significantly enriched in IC, and the tar yield is 1.08% lower than that of raw coal. The tar composed more polycyclic aromatic hydrocarbons such as biphenyl, naphthalene and benzene series. The maceral macro separation of low-rank coal effectively realizes the separation and enrichment of different type of components in coal, which was beneficial to its subsequent high-value cascade.