Physicochemical properties of chars at different treatment temperatures

Abstract

In this study, the physicochemical properties of the char of Indonesian SM coal following heat treatment at various temperatures were evaluated using X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and morphological and specific surface area analysis. Based on these analyses, heat treatment of coal was determined to be the most effective in increasing the coal rank. In the XPS analysis, the C-O and C-O-C groups and quaternary-N species were found to be of a lower grade coal when the pretreatment temperature decreased, meanwhile the C-C group and pyridinic species increased. In the FT-IR analysis, the collapse of the C-O and C-O-C group was observed due to the collapse of the ether group. In SEM and Brunauer-Emmett-Teller (BET) analysis, a decrease in the ether group was shown to be accompanied with the formation of micropores.Implications: Recently, XPS analyses have been reported as coal surface analysis. Usually, they have reported the analysis of the coals with different rank. This study investigated the coal surface characteristics of the coals pretreated at different temperature using various analyses (BET, SEM, XPS, FT-IR), and this study can be the basis for other research and applications.

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“…The spectrum of C 1s can be resolved into four characteristic peaks at 284.8 eV (C–C), 286.4 eV (C–O), 287.5 eV (C–O–C) and 288.9 (C–F), respectively. 35–37 The N 1s spectrum shows the peaks at 407.65 eV (–NO 3 ). 38 The O 1s spectrum was resolved into three peaks at 533.6 eV (O–NO 2 ), 532.5 eV (C–O–C) and 532.0 eV (SiO 2 ).…”