Desorption behavior of gas in primary coal and tectonic coal under low-temperature environments: a comparative study

Coal and gas outburst prevention remains a formidable technical challenge. Considering the widespread coexistence of primary and tectonic coal in most coal-mining regions in China, clarifying their gas desorption behaviors under low-temperature conditions is crucial for the further application of cryogenic freezing technology for outburst prevention. A self-developed apparatus was used to investigate methane adsorption–desorption behaviors of primary and tectonic coals under low-temperature environments. The results indicate that tectonic coal exhibits a greater actual methane desorption volume than primary coal under low-temperature conditions, and the inhibitory effect of low temperature on methane desorption is more pronounced for tectonic coal. Although primary coal generally exhibits a higher diffusion coefficient than tectonic coal under low-temperature conditions, it exhibits a greater degree of attenuation with time and temperature variation. Among the diffusion models examined, the exponential model yielded the best-fitting results for characterizing methane desorption from primary and tectonic coal under low-temperature conditions. These findings offer a theoretical basis for advancing the development and practical implementation of cryogenic freezing as a strategy for coal and gas outburst prevention.