Latent methane in fossil coals

• Published in: Fuel (Guildford) Vol. 83; no. 10; pp. 1407 - 1411
• Main Authors: Alexeev, A.D, Ulyanova, E.V, Starikov, G.P, Kovriga, N.N
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2004; Elsevier
• Subjects: Applied sciences; Coal and derived products; Coalbed methane; Desorption; Energy; Exact sciences and technology; Fuels; NMR; Structure, chemical and physical properties; X-ray diffraction; X-ray diffraction; NMR; Desorption; Coalbed methane; Methane; Coal deposit; Coal seam gas; NMR spectrometry; Porosity; Nuclear magnetic resonance; X ray diffractometry
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2003.07.001

It is established experimentally using 1H NMR wide line spectroscopy that methane can exist in coals not only in open or closed porosity and fracture systems but also in solid solutions in coal substance, in particular, under methane pressure 2 MPa or higher. Methane dissolved in coal minerals reversibly modifies their lattice parameters as determined from X-ray diffraction analysis. Co-existence of these methane forms in fossil coals causes multi-step desorption kinetics. It is shown experimentally that the long-term latent methane desorption is effected mainly by closed porosity, which in turn is determined by coal rank.