INTERDEPENDENCE BETWEEN METHANE PHASE STATES AND GAS-CONTENT IN THE COAL STRATA

Details

Parent Category: Geo-Technical Mechanics, 2015

Category: Geo-Technical Mechanics, 2015, Issue 120

UDC[622.411.332:533.17]:622.272.63

Authors:

SkipochkaS. I., D.Sc. (Tech.), Professor

Palamarchuk Т. А., D.Sc. (Tech.), Principal Researcher

(IGTM NAS of Ukraine)

Abstract:

Subject of the research: phase states of methane in the coal strata. Objective of the research: to assess contribution of methane phase state to the gas content in the coal strata. Method of the research: analytical, with using main principles of thermodynamics.

Calculation formulas are proposed, and maximally possible volumes of methane which can be in a coal stratum not disturbed by mining operations are evaluated. Calculations were made for four methane phase states accepted in classical concepts of methane content in a stratum: free; adsorbed; absorbed in the form of solid coal-methane solution; and hydrated. Values are specified for methane-molecule concentration in the solid solution and free state, and an equation is presented for evaluating density of adsorbed methane. Partial pressures of methane molecules in the solid solution are determined. It is shown that content of methane in the solid solution is considerably less than in the free and adsorbed states. Content of hydrated components in the real conditions does not exceed 2-3% of total volume of methane.

By comparing the calculated values with measurements at gas-dynamic phenomena, it is concluded that classical representation only partly explain anomalous occurrences of methane, and the cause should be sought at the atomic and molecular level of coal.

Keywords: coal strata, gas content, phase states of methane.

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About the authors:

Skipochka Sergey Ivanovich, Doctor of Technical Sciences (D. Sc), Professor, Head of Rock Mechanics Department, M. S. Polyakov Institute of Geotechnical Mechanics under the National Academy of Sciences of Ukraine (IGTM, NASU), Dnepropetrovsk, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.

Palamarchuk Tatyana Andreevna, Doctor of Technical Sciences (D. Sc), Senior Researcher, Principal Researcher in Rock Mechanics Department, M. S. Polyakov Institute of Geotechnical Mechanics under the National Academy of Sciences of Ukraine (IGTM, NASU), Dnepropetrovsk, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.

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