Change of parameters in molecular structure of Donbas coals under the influence of external factors

Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine, 49005, Dnipro, Simferopolska Str., 2a, Ukraine

^* Corresponding author: gvrvg@meta.ua

Abstract

The molecular structure of coal is estimated by 13 parameters of infrared spectra, electron paramagnetic resonance, volatile yield and ash content. A new criterion of hydrophobicity is applied, which has shown its informativeness in analyzing the molecular structure of coals of various ranks. It is more sensitive to changes in coal rank than the standard index of volatile yield. The coalification process leads to a significant increase in this index due to the water release and other hydroxyl-containing compounds from the substance of coal. Two-way analysis of variance showed that the influence of the metamorphism factor is significant for 9 molecular parameters. The strongest effects are manifested in the sorption capacity, the criterion of hydrophobicity and the number of paramagnetic centers. The stratigraphic factor does not have a significant impact on one of the molecular parameters. Factor analysis by the method of principal components of the molecular structure of coal showed that the most significant independent factors are metamorphism and sedimentation conditions, the latter ones include independent processes: accumulation of mineral components, decomposition of biomass and geochemical environment during the sedimentation period.