Fractal characterization on methane adsorption in coal molecular structure

The research and analysis on the heterogeneous characterization of adsorbed methane in coal at the molecular scale has not yet been fully explored. In this paper, the complex system of the coal molecular structure adsorbed methane was constructed based on the Langmuir adsorption equation and molecular simulation. A fractal characterization model to analyze the heterogeneous distribution of adsorbed methane in coal molecular structure was established, and the principle and method of the proposed model is specifically derived and summarized. The quantization relation between the fractal dimension (Df) for the methane adsorption of coal molecular structure and the adsorption pressure (P) was established, which is similar to the variation of adsorption capacity with adsorption pressure of the Langmuir equation. This research achieved a breakthrough in the fractal characterization of methane adsorption by coal at the molecular scale and further revealed the control of fractal structure over fractal behavior. The proposed analysis and characterization method provides insight into a deeper understanding of the gas adsorption mechanism of coal-based or carbon-based materials, which is conducive to creating a significant basis for the novel fractal design strategies of coal-based materials.