Molchanov A. Scientific basis of estimating the state, sorption kinetics, and properties of the coal-water-methane system

The work is devoted to urgent scientific and applied problem of enhancing the reliability of the state, sorption kinetics, and properties estimates in the case of fluid saturated coal substance. A number of new important results have been obtained in the course of extensive studies. It was revealed that parameters of Raman spectra in coals correlate with volatile content, which enabled to propose a new criterion for coals classification in the metamorphism sequence. Physical states of methane and water occluded in coal porous structure were established. Methane diffusion coefficient and its time, temperature, and/or pressure dependences in various coal structures were evaluated. It was shown that surface layer formation at water adsorption on a coal pore surface is governed by the cluster mechanism and that the mechanism of pore filling with saturated vapors is realized. Methane mass transfer model was developed accounting for both filtration and solid state diffusion. It was found that the filtration plays a key role in the case of small coal bodies while in the case of coal massif the diffusion participates nearly to the same extent. Kinetics of structural transformations in the coking coal under high hydrostatic pressure up to 1000 MPa was studied experimentally, mobile hydrocarbon components being determined using 1H NMR technique. It was assumed that these components are based on methyl groups (-CH3) from coal aliphatic. Several techniques were developed for in-mine studies.