Methane sorption on brown and sapropelite coals

Based on the results of IR-spectroscopic and gas-chromatographic analysis, the release and absorption of methane on the modification of Kizelovsk brown coal, Barzas sapromixite, and Balkhash alginite was considered. The dispersion of strong bulk aggregates of brown coal to particles of size 0.1–1.2 mm resulted in the release of methane; the process was enhanced as the temperature was increased from −35 to 200°C. Brown coal particles became incapable of generating CH4 and intensely chemisorbed it as the coal matter became alkylated and esterified by methanol vapor at 67°C. This transition occurred under mild conditions in a laboratory experiment without the use of special catalysts at comparatively small CH3OH additives to brown coal (no more than 1.5 ml/g). Brittle particles of flag barzassite and rubberlike balkhashite did not generate methane; however, they changed from initially slow physical adsorption of CH4 in native particles to intense chemisorption upon interaction with methanol at 67°C (to 0.3 ml of CH3OH per gram of balkhashite and to 1.2 ml per gram of barzassite)