Study on the Differences of Chemical Structures and Pyrolysis Characteristics between the Jurassic and Carboniferous Coking Coals

Abstract

Using Jurassic coking coals and Carboniferous coking coals as raw materials, carbonization experiments were carried out on the cokes produced by them in a self-made furnace in a laboratory-scale coking furnace, finding that the coke quality of the Jurassic fat coals and coking coals was obviously inferior to that of the Carboniferous coking coals of the same brand. In this study, the reasons for this phenomenon were studied by elemental analysis, Fourier transform infrared spectroscopy analysis, and thermogravimetric analysis of experimental coal samples and by combining the differences in chemical structures of experimental coal samples with pyrolysis characteristic parameters. It was found that the key factor affecting the quality of cokes made from the Jurassic fat coals, coking coals, and highly volatile coking coals was that the coals contained too many oxygen-containing functional groups, which were decomposed into reactive oxygen species in the main pyrolysis stage of coal. These reactive oxygen species would consume too much free-moving hydrogen and then trigger a large number of condensation and cross-linking reactions, resulting in poor plastic mass and coke quality.

Co-Carbonization of Discard Coal with Waste Polyethylene Terephthalate towards the Preparation of Metallurgical Coke

“…In the results in Figure 9 a, it can be seen that the c-PET/d-coal samples showed a higher thermal stability under pyrolysis conditions, which may be due to a lesser amount of volatile compounds present in the c-PET/d-coal samples compared to their d-coal counterparts. In all samples, the peak decomposition temperature in argon was found to lie between 700 and 800 °C, which is attributed to the complete removal of volatile compounds such as C x H y , NO x , and SO x via different pathways such as cracking and chain scission reactions [ 47 ]. The region of complete decomposition under pyrolysis conditions is typically followed by the formation of a char residue, which shows little to no changes in weight loss at high temperatures.…”

Infrared Spectrum and Principal Component Analysis of Heavy Tar Cut by Different Fractions from Tar-Rich Coal

“…This suggests that aromatic rings contain numerous substituents . Specific to the aromatic substituted hydrocarbons, CH (adjacent H, adjacent 2H, and adjacent 4H) exhibits characteristic peaks at 875, 810, and 750 cm –1 , respectively . However, these peaks have relatively weak intensities, and the intensity of their vibrational peak decreases as the distillation temperature rises.…”

“…21 Specific to the aromatic substituted hydrocarbons, CH (adjacent H, adjacent 2H, and adjacent 4H) exhibits characteristic peaks at 875, 810, and 750 cm −1 , respectively. 22 However, these peaks have relatively weak intensities, and the intensity of their vibrational peak decreases as the distillation temperature rises. This phenomenon implies that the increased distillation temper-ature leads to a bridge bond within the functional group of aromatic hydrocarbons.…”