Title: The coal-gas system - the effective diffusion coefficient

Authors: Norbert Skoczylas; Juliusz Topolnicki

Addresses: Strata Mechanics Research Institute of The Polish Academy of Sciences, ul. Reymonta 27, 30-059 Krakow, Poland ' Strata Mechanics Research Institute of The Polish Academy of Sciences, ul. Reymonta 27, 30-059 Krakow, Poland

Abstract: In this paper issues concerning the evaluation of the kinetics of gas release from coal samples were systematised. Our own analytical solution was presented. Diffusion equation was solved numerically. The numerical solution of Fick's formula taking into account of the Langmuir isotherm was compared with the analytical solution based on the Henry isotherm. For the initial range of pressure values, where Langmuir and Henry isotherms were similar, the differences were relatively minor. However, they become significant for the higher pressure values. [Received: January 8, 2015; Accepted: March 4, 2015]

Keywords: coal-gas systems; gas diffusion; Fick's law; sorption isotherms; effective diffusion coefficient; gas release kinetics; pressure values; coal mining.

DOI: 10.1504/IJOGCT.2016.077300

International Journal of Oil, Gas and Coal Technology, 2016 Vol.12 No.4, pp.412 - 424

Received: 09 Jan 2015
Accepted: 04 Mar 2015
Published online: 28 Jun 2016 *