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.