Factors influencing the gas adsorption thermodynamic characteristics of low-rank coal

Low-temperature nitrogen and isothermal adsorption experiments were conducted on six typical low-rank coal samples from the Fukang mining area, Xinjiang, PR China. Using different temperatures, the effects of the coal’s pore structure on gas adsorption and other thermodynamic characteristics were an...

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Bibliographic Details
Published inFuel (Guildford) Vol. 248; pp. 117 - 126
Main Authors Yan, Min, Bai, Yang, Li, Shu-Gang, Lin, Hai-Fei, Yan, Dong-Jie, Shu, Chi-Min
Format Journal Article
LanguageEnglish
Published Kidlington Elsevier Ltd 15.07.2019
Elsevier BV
Subjects
Adsorption
Adsorption free-energy
Coal
Coal mines
Coal mining
Energy
Enthalpy
Entropy
Fractal dimension
Fractal geometry
Free energy
Heat
Heat of adsorption
Isosteric heat of adsorption
Isothermal adsorption
Low temperature
Mathematical analysis
Pore structure
Porosity
Specific surface
Surface area
Surface chemistry
Isothermal adsorption
Isosteric heat of adsorption
Fractal dimension
Pore structure
Adsorption free-energy
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Summary:Low-temperature nitrogen and isothermal adsorption experiments were conducted on six typical low-rank coal samples from the Fukang mining area, Xinjiang, PR China. Using different temperatures, the effects of the coal’s pore structure on gas adsorption and other thermodynamic characteristics were analyzed. The Clausius–Clapeyron equation was used to calculate the isosteric heat of adsorption, and the standard adsorption equilibrium constant was derived to calculate the adsorption free-energy and entropy. The relationships between pore structure characteristics and gas adsorption thermodynamic parameters were investigated. The results showed that the adsorption free-energy and enthalpy of the coal samples decreased with an increase in temperature. Adsorption heat and adsorption entropy were affected by an increase in pore volume and specific surface area. The specific surface area and transition pore volume exhibited quadratic relationships with the free-energy and total pore volume, whereas the mesopore volume exhibited a positive linear relationship with the adsorption free-energy. No prominent relationships among average pore diameter, adsorption heat, adsorption free-energy, and adsorption entropy were observed. No correlation was identified between micropore volume and adsorption free-energy. Fractal dimension was linearly and positively related to the adsorption heat and entropy but had no effect on the free-energy.
ISSN:0016-2361
1873-7153
DOI:10.1016/j.fuel.2019.03.064