Decomposition of the Gas–Coal Solid Solution in Coal Beds: Energy Analysis

A gas–coal solid solution is shown to be a metastable form of methane molecules in the coal microstructure. Its decomposition on account of molecular repulsion occurs when the pressure in the coal bed is released. It is also established that the gas content of the coal bed consists of the methane formed in the coal bed over its entire geological existence and cannot be estimated by means of the Langmuir formula. A model developed for the decomposition of the gas–coal solid solution yields a mathematical equation describing this process.