Deformation of Nanoporous Materials in the Process of Binary Adsorption: Methane Displacement by Carbon Dioxide from Coal

The phenomenon of adsorption-induced deformation of nanoporous materials has recently attracted a lot of attention in chemical, materials, and geoscience communities. Various theoretical and molecular simulation approaches have been suggested to predict the stress and strain induced by single component gas adsorption. Here, we develop a thermodynamic method based on the notion of the adsorption stress to predict the deformation effects upon multicomponent adsorption. As a practically important example, the process of the displacement of methane by carbon dioxide from microporous carbons is considered. This process is the foundation of secondary gas recovery from shales and coalbeds associated with carbon dioxide sequestration. Theoretical predictions are correlated with the original experimental data on CO2 and CH4 individual and binary adsorption on coal samples coupled with in situ strain measurements. With the model parametrized and verified against the experimental data at ambient temperature, the projections are made for the adsorption deformation at geological conditions of elevated pressure and temperature, which increase with the depth of the reservoir. The proposed approach may have multifaceted applications in modeling the behavior of hydrocarbon mixtures in nanoporous geomaterials, gas separations, and energy storage on flexible adsorbents.

Automated summary

The phenomenon of adsorption-induced deformation of nanoporous materials has been studied recently, with a thermodynamic method developed to predict the effects of multicomponent adsorption. The research findings can be applied to model the behavior of hydrocarbon mixtures in nanoporous geomaterials and energy storage on flexible adsorbents.