Rapid analysis of phase behavior with density functional theory. II. Capillary condensation in disordered porous media

2003 ◽  
Vol 118 (16) ◽  
pp. 7466 ◽  
Author(s):  
Laura J. Douglas Frink ◽  
Andrew G. Salinger
Keyword(s):  
Density Functional Theory ◽  
Porous Media ◽  
Phase Behavior ◽  
Density Functional ◽  
Capillary Condensation ◽  
Rapid Analysis ◽  
Functional Theory ◽  
Disordered Porous Media

Phase Behavior and Adsorption of Pure Substances and Mixtures and Characterization in Nanopore Structures by Density Functional Theory

SPE Journal ◽  
2014 ◽  
Vol 19 (06) ◽  
pp. 1096-1109 ◽  
Author(s):  
Zhidong Li ◽  
Zhehui Jin ◽  
Abbas Firoozabadi
Keyword(s):  
Density Functional Theory ◽  
Porous Media ◽  
Phase Change ◽  
Pore Structure ◽  
Phase Behavior ◽  
Density Functional ◽  
Functional Theory ◽  
Pure Substances ◽  
Slit Pores ◽  
Carbon Slit Pores

Summary Phase behavior in shale remains a mystery because of various complexities and effects. One complexity is from nanopores, in which phase behavior is significantly affected by the interaction between the pore surfaces and fluid molecules. The result is the heterogeneous distribution of molecules that cannot be described by bulk-phase thermodynamic approaches. Statistical thermodynamic methods can describe the phase behavior in nanopores. In this work, we apply an engineering density functional theory (DFT) combined with the Peng-Robinson equation of state (EOS) to investigate the adsorption and phase behavior of pure substances and mixtures in nanopores, and include the characterization of pore structure of porous media. The nanopores are represented by carbon-slit pores each consisting of two parallel planar-infinite structureless graphite surfaces. The porous media are activated carbons and dry coal, each modeled by an array of polydisperse carbon-slit pores. We study the influence of multiple factors on phase transitions of various pure light species and their mixtures in nanopores. We find that capillary condensation and hysteresis are more likely in heavier hydrocarbons, at lower temperatures, and in smaller pores. For pure hydrocarbons in nanopores, the phase change always occurs below the critical temperature and saturation pressure. For mixtures in nanopores, there may be a phase change above the cricondentherm. We characterize the pore structure of porous media to obtain the pore-size distribution (PSD), surface area (SA), and pore volume (PV) on the basis of the measured adsorption isotherms of pure substances. Then, we use the computed PSD to predict the adsorption of mixtures in porous media. There is agreement between the experiments and our predictions. This work is in the direction of phase-behavior modeling and understanding in shale media.

scholarly journals Active binary switching of soft colloids: stability and structural properties

Soft Matter ◽  
2021 ◽  
Author(s):  
Michael Bley ◽  
Joachim Dzubiella ◽  
Arturo Moncho Jorda
Keyword(s):  
Density Functional Theory ◽  
Phase Behavior ◽  
Structural Properties ◽  
Brownian Dynamics ◽  
Density Functional ◽  
Equilibrium Structure ◽  
Functional Theory ◽  
Binary Switching ◽  
Soft Colloids ◽  
Non Equilibrium

We employ reactive dynamical density functional theory (R-DDFT) and reactive Brownian dynamics (R-BD) simulations to study the non-equilibrium structure and phase behavior of an active dispersion of soft Gaussian colloids...

scholarly journals The Effect of Topology on Phase Behavior under Confinement

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1220
Author(s):  
Arnout M. P. Boelens ◽  
Hamdi A. Tchelepi
Keyword(s):  
Phase Behavior ◽  
Density Functional ◽  
Capillary Condensation ◽  
Good Description ◽  
Functional Theory ◽  
Minkowski Functionals ◽  
First Order ◽  
Lennard Jones ◽  
And Topology ◽  
First Order Transition

This work studies how morphology (i.e., the shape of a structure) and topology (i.e., how different structures are connected) influence wall adsorption and capillary condensation under tight confinement. Numerical simulations based on classical density functional theory (cDFT) are run for a wide variety of geometries using both hard-sphere and Lennard-Jones fluids. These cDFT computations are compared to results obtained using the Minkowski functionals. It is found that the Minkowski functionals can provide a good description of the behavior of Lennard-Jones fluids down to small system sizes. In addition, through decomposition of the free energy, the Minkowski functionals provide a good framework to better understand what are the dominant contributions to the phase behavior of a system. Lastly, while studying the phase envelope shift as a function of the Minkowski functionals it is found that topology has a different effect depending on whether the phase transition under consideration is a continuous or a discrete (first-order) transition.

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