Construction of a noise Algorithm–Based three-dimensional porous adsorption model of coal and study of coal-oxygen physisorption kinetics

• Published in: Microporous and mesoporous materials Vol. 390; p. 113580
• Main Authors: Song, Zhifan, Dong, Zhiyu, Lu, Zhifan, Ren, Kaiwen, Xie, Peng, Wang, Junfeng
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.05.2025
• Subjects: Kinetics; Noise algorithm; Numerical simulation; Physical adsorption; Spontaneous coal combustion; Noise algorithm; Numerical simulation; Spontaneous coal combustion; Kinetics; Physical adsorption
• ISSN: 1387-1811
• DOI: 10.1016/j.micromeso.2025.113580

In view of the difficulty of accurately characterizing the dynamic process of coal-oxygen physisorption using existing models, this study constructed three-dimensional (3D) porous adsorption models of coal based on a noise algorithm, and the kinetics of coal oxygen physisorption was investigated based on this model. The degree of metamorphism and pore characteristics of the coal samples were determined via industrial analysis and pore structure characterization, and high-pressure isothermal adsorption experiments were carried out to determine the isothermal adsorption lines of coal oxygen at different temperatures. The experimental data were fitted to construct a mathematical model under the joint influence of temperature and pressure, and a 3D porous adsorption model for coal was constructed based on the experimental results to explore the adsorption kinetic process. Revealing that the amount of oxygen adsorbed was negatively correlated with temperature, and coal samples with less deterioration possessed larger specific surface areas and pore volumes, resulting in a stronger oxygen adsorption ability. The coal-oxygen isothermal adsorption data fitted well with the Langmuir adsorption model, and the fitted oxygen adsorption values were similar to the experimental data. Numerical simulations using the constructed models indicated that the adsorption process of oxygen on the coal particle surface could be divided into three stages: (1) the seepage stage, in which oxygen is adsorbed by the outer surface of the coal body and its surface pores; (2) the surface diffusion stage, in which oxygen diffuses to the inner region of the coal particles through their pores; and (3) the deep adsorption stage, in which oxygen is adsorbed in the deep pores of the coal particles, enabling complete adsorption. Coal-oxygen adsorption reached equilibrium in a short time, the amount of oxygen adsorbed rapidly increased during the initial stage of adsorption, approaching the maximum value at 0.4 ms, and then the adsorption rate gradually decreased into the slow adsorption stage, finally reaching equilibrium at 1.0 ms. The model results indicated that oxygen adsorption was negatively correlated with temperature and positively correlated with adsorption equilibrium pressure, which aligned with the experimental rule. [Display omitted] •This article establishes a 3D structural model of coal based on noise algorithm.•Studied the process of oxygen permeation from coal surface to internal pores.•Analyzed temperature and pressure effects on coal's oxygen adsorption.