New Model for Coal Gas Diffusion Based on the Fractal Tree-Like Bifurcation Network Structure

Area of Science:

• Geosciences
• Chemical Engineering
• Materials Science

Background:

• Understanding gas diffusion in coal is crucial for energy extraction and safety.
• Existing models often oversimplify the complex porous structure of coal.

Purpose of the Study:

• To develop a novel fractal diffusion model for nonstationary gas transport in coal.
• To establish quantitative relationships between diffusion coefficients, temperature, pressure, and coal microstructure.

Main Methods:

• Developed a fractal diffusion model incorporating a treelike bifurcation network.
• Considered pore tortuosity and connectivity for enhanced realism.
• Validated the model using experimental data and comparison with existing models.

Main Results:

• The model accurately describes gas diffusion, accounting for pore structure complexities.
• Sensitivity analysis showed gas diffusion is highly sensitive to pressure variations.
• Temperature and pressure are key influencers at the initial diffusion stages.

Conclusions:

• The fractal diffusion model provides a more realistic representation of gas transport in coal.
• Pressure is identified as the dominant factor influencing gas diffusion dynamics.
• The findings aid in optimizing gas extraction and understanding coalbed methane behavior.