Szczegóły publikacji
Opis bibliograficzny
Diffusion coefficients of $CO_2$ in coal as material constants: estimation errors arising from the assumption of spherical grains / Katarzyna Kozieł, Mateusz Kudasik, Anna Pajdak, Kamil Soucek, Juliusz Topolnicki, Norbert SKOCZYLAS // Energy & Fuels ; ISSN 0887-0624 . — 2026 — vol. 40 iss. 23, s. 12428–12441. — Bibliogr. s. 12440–12441, Abstr. — Publikacja dostępna online od: 2026-05-29
Autorzy (6)
- Kozieł Katarzyna A.
- Kudasik Mateusz
- Pajdak Anna
- Soucek Kamil
- Topolnicki Juliusz
- AGHSkoczylas Norbert
Dane bibliometryczne
| ID BaDAP | 168507 |
|---|---|
| Data dodania do BaDAP | 2026-06-29 |
| Tekst źródłowy | URL |
| DOI | 10.1021/acs.energyfuels.6c01292 |
| Rok publikacji | 2026 |
| Typ publikacji | artykuł w czasopiśmie |
| Otwarty dostęp |  |
| Czasopismo/seria | Energy & Fuels |
Abstract
This study introduces a new planetary model of gas diffusion within coal grains exhibiting nonideal geometric shapes. The model was developed to overcome the limitations of the classical Crank model, which assumes perfectly spherical grains and consequently produces systematic errors in estimating the effective diffusion coefficient (De) for naturally occurring porous materials. In the planetary model, an individual grain is represented as a system composed of a central sphere (“planet”) surrounded by a set of smaller spheres (“satellites”). This representation enables a parametric description of the true geometric irregularity of grains while retaining the analytical form of the diffusion equation solution. Experimental investigations were performed for five types of Polish coals─from hard to lignite─covering a broad range of coalification degrees. Grain geometry was characterized using high-resolution X-ray computed tomography (CT), whereas CO2 sorption kinetics were determined using an isobaric volumetric apparatus. Model parameters were fitted to the experimental data using an optimization algorithm combining simulated annealing and Monte Carlo methods. The planetary model provided a markedly improved fit to the experimental sorption curves. The enhancement in estimation quality relative to the Crank model ranged from 2- to 10-fold. The resulting diffusion coefficients were, on average, three to five times lower than those obtained with the spherical model, indicating that neglecting the true grain geometry leads to systematic overestimation. Additionally, the optimized number of satellites N exhibited an exponential correlation with the degree of coalification, serving as a quantitative indicator of grain morphological complexity. The proposed planetary model enables more realistic determination of diffusion coefficients and establishes a foundation for integrating tomographic data into diffusion kinetics analysis in porous materials.
