Evolution of gaseous products and analysis of methane generation reaction types during pyrolysis of Shuicheng lignite

The Fourier transform infrared (FT-IR) spectroscopy was applied to investigate the functional groups of Shuicheng lignite, and the simultaneous thermogravimetry-mass spectrometry (TG/MS) at heating rate of 10 ℃/min was used to investigate the pyrolysis behavior of coal. The instantaneous evolution of the gaseous products (H₂, CH₄, H₂O, CO, CO₂) was studied by means of temperature-programmed pyrolysis experiments. The pyrolytic generation characteristics of methane was specially analyzed. Five peaks were fitted and the kinetic parameters were calculated by the fitting of curves. By the kinetic analysis combined with structure analysis, pyrolysis characteristics and the evolution features of other volatiles during pyrolysis, it is found that the lowest temperature peak represents the desorption of adsorbed methane in coal and the other four peaks are the results of methane generation during pyrolysis, which involves four types of reactions.