Molecular Simulation of Adsorption Processes in Coal Materials

Molecular simulation has emerged as a powerful tool to probe the fundamental interactions governing gas–solid behaviour in coal, offering atomistic insight into adsorption, diffusion and competitive binding of CH₄, CO₂, N₂ and H₂O within complex organic matrices. By constructing realistic coal macromolecular models and applying Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) methods, researchers can predict equilibrium isotherms, map energy profiles and visualise pore occupancy under varying pressures, temperatures and moisture conditions. These simulations reveal how pore size distribution, coal rank and in situ stress influence adsorption capacity, selectivity and transport kinetics. The Langmuir adsorption isotherm and isosteric heat calculations facilitate thermodynamic characterisation, while diffusion coefficients derived from MD inform on gas mobility and overall extraction efficiency. This body of work underpins strategies for enhanced coalbed methane recovery, CO₂ sequestration, spontaneous combustion prevention and mine‐safety gas management, illustrating global significance across energy, environmental and industrial applications.

Research from Nature Portfolio

Recent studies have employed GCMC and MD to elucidate competitive adsorption in lignite, demonstrating that CO₂ preferentially occupies adsorption sites over CO, O₂ and N₂ at low pressure and that water content and injection gases can promote CO desorption in goaf environments. Investigations of inert gas injection into bituminous coal reveal that high‐pressure N₂ enhances CH₄ desorption primarily through competitive displacement and diffusion dilution, with the efficiency of methane removal increasing with injection pressure and system temperature. Complementary work on coking coal under varying in situ stresses shows that increased stress reduces pore volume and surface area, leading to diminished methane uptake that continues to follow a Langmuir‐type adsorption curve. These findings link mechanical deformation to pore evolution and adsorption performance, offering mechanistic insight for stress‐controlled reservoir engineering.

Molecular Simulation of Adsorption Processes in Coal Materials publication trend

The graph below shows the total number of articles in molecular simulation of adsorption processes in coal materials across all publications each year (not limited to Nature Index journals).

Technical terms

Grand Canonical Monte Carlo: computational method for sampling adsorption equilibria at fixed chemical potential, temperature and volume.

Molecular Dynamics: simulation technique for tracking atomic trajectories over time to extract diffusion coefficients and dynamic behaviour.

Langmuir adsorption isotherm: model describing monolayer gas uptake on homogeneous surfaces as a function of pressure.

Coal macromolecular model: atomistic representation of coal’s organic network, including aromatic clusters and functional groups.

Micropore: pore with diameter less than 2 nm, serving as primary adsorption sites for gas molecules.

Competitive adsorption: simultaneous uptake of multiple gas species, where stronger adsorbates displace weaker ones from binding sites.

References

1. Molecular simulation of gases competitive adsorption in lignite and analysis of original CO desorption. Scientific Reports (2021).
2. Simulation study on dynamic characteristics of gas diffusion in coal under nitrogen injection. Scientific Reports (2022).
3. Evolution of pore characteristics and methane adsorption characteristics of Nanshan 1/3 coking coal under different stresses. Scientific Reports (2022).
4. Simulation Study on Molecular Adsorption of Coal in Chicheng Coal Mine. Molecules (2023).
5. Molecular Simulation on Competitive Adsorption Differences of Gas with Different Pore Sizes in Coal. Molecules (2022).
6. Molecular Simulation of the Adsorption Characteristics of Methane in Pores of Coal with Different Metamorphic Degrees. Molecules (2021).