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

Abstract

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 CO 2 and CH 4 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.

Deformation of Nanoporous Carbons Induced By Multicomponent Adsorption: Insight from the SAFT-DFT Model

“…We utilize the theoretical approach for the deformation of a nanoporous solid in equilibrium with an adsorbed mixture originally developed in ref . In brief, we consider a thermodynamic system with an adsorbent in equilibrium with a gas mixture of a given composition { y i }, external pressure p ext , and temperature T .…”

“…The key to the adsorption stress approach is the ability to calculate the adsorption isotherms and grand thermodynamic potential in pores of different sizes. This can be done by different means using various DFT models, − Monte Carlo (MC) simulations, , or by phenomenological adsorption models, like Derjaguin-Brookhoff-de Boor (DBDB), Langmuir, − and Dubinin models.…”

“…In a recent work from our group, we proposed a method to determine the adsorption-induced deformation upon the adsorption of binary mixtures using only the pure-component adsorption and strain isotherms . We employed the Langmuir model to calculate the adsorption grand thermodynamic potential and the adsorption stress for pure CO 2 and methane adsorption in Polish hard coals.…”

Study on the Nanopore Deformation Mechanisms in Shale Oil Reservoir: Insights from the Molecular Simulation

“…In the field of adsorption motivation pore deformation, the relevant studies have been conducted in the following two areas: the study of shale nanopore adsorption patterns and the study of the relationship between the amount of adsorption and deformation motivation by it. − The microscopic studies on the adsorption law of the CO 2 -multicomponent alkane system are still relatively limited, and there is a lack of studies on shale multicomponent fluid adsorption motivation deformation. However, the synergistic effect of pore pressure field and deformation field and the coupling effect of adsorption and deformation have not been considered yet.…”

“…The synergistic deformation amount decreases with temperature increase. When the temperature changes from 333 to 433 K, the maximum synergistic deformation amount decreases from 37 24. to 25.59%.…”