Evaluation of chemical structure, pyrolysis reactivity and gaseous products of Shenmu coal of different particle sizes

In this study, chemical structure and pyrolysis reactivity of six different coal particle fractions were researched using Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA), respectively. An on-line FTIR was applied to assess the evolution characteristics of the gaseous products. The results expose that with the particle size decreasing, the ash content of Shenmu coal sample gradually increases, while the pyrolysis reactivity steadily decreases. In addition, the content of hydrogen as well as some typical chemical groups in coal is also affected by particle size. In our experimental conditions, the comprehensive infrared structural parameter has a good linear relation with pyrolysis reactivity. Moreover, with the particle size decreasing, the release amount of CH₄, aliphatic hydrocarbons and light aromatic hydrocarbons gradually decreases, while the release amount of CO changes little.