Pyrolysis characteristics of ethanol swelling Shendong coal and the composition distribution of its coal tar

Abstract

The structural features and pyrolysis characteristics of Shendong demineralized coal (DC) and its ethanol swelling coal (EDSC) were investigated by Fourier transform infrared (FTIR), solid-state cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C-NMR), thermo-gravimeter-Fourier transform infrared (TG-FTIR) spectroscopy, the self-made steel retort assay, and pyrolysis gas chromatography-mass spectrometer (Py-GC/MS). The pyrolysis product coal tar from the self-made steel retort assay was extracted by n-hexane to obtain the n-hexane solubles (CTHS) as well as the n-hexane insolubles (CTHIS). The composition of CTHS has been explored by the analysis of GC/MS, and CTHIS was investigated by the analyses of TG-FTIR and Py-GC/MS. The analysis data display that the coal tar yield of EDSC increases by 0.42 wt% and the semi-coke yield of EDSC decreases by 1.33 wt%. The intensity of −OH stretching vibration at 3405 cm−1 in the FTIR spectra of EDSC is weakened and the peak moves to the low wave number. Aliphatic carbons and aromatic carbons of EDSC decrease. The content of neutral compounds in EDSC pyrolysis tar increases by 2.01 wt%. CTHIS mainly includes phenols, alkanes, aromatics and pyridine. Phenolic compounds and nitrogen-containing heterocyclic compounds in the pyrolysis volatiles of EDSC-CTHIS increase by 1.12 wt% and 1.46 wt%, respectively.