Molecular Simulation of H2O, CO2, and CH4 Adsorption in Coal Micropores

Han, Jianchao; Bogomolov, A. Kh.; Makarova, Elena Yu.; Yang, Zhaozhong; Lü, Yanjun; Han, Jun; Li, Yong

doi:10.1134/s199079311804022x

Cited by 12 publications

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References 12 publications

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“…Then, the value reaches a plateau and remains stable at high pressure. 3,44,50,51,53,98 Additionally, CO 2 exhibits a higher adsorption amount and better adsorption capacity than does CH 4 , revealing that CO 2 has a better affinity toward the coal model. 11,17,36,44,47,51,98,99 This simulation result is also in line with the experimental result obtained for 8 types of Indian bituminous coal, in which CH 4 achieved 1 mmol/g adsorption, whereas CO 2 yielded 1.5−4 mmol/g.…”

Section: Simulation Resultsmentioning

confidence: 98%

“…The adsorption isotherm is a criterion used to examine the adsorption capacity of a gas under diverse temperatures and pressures. ,,,,− ,,,,,,,, …”

Section: Simulation Resultsmentioning

confidence: 99%

“…The isosteric heat of adsorption is an important thermodynamic parameter for evaluating energy liberation, and displaying the strength of an interaction. ,, The following formula is used to investigate the adsorption characteristics, ,,,,,, where Q st is the isosteric heat of adsorption in the absolute number of n (kJ/mol), R g is the gas content (kJ/(mol·K)), T is the temperature (K), U ad is the total adsorption energy for the adsorbed phase (kJ), and N ad is the total molar number of adsorbates of n (mol).…”

Section: Simulation Resultsmentioning

confidence: 99%

“…The adsorption isotherm is a criterion used to examine the adsorption capacity of a gas u n d e r d i v e r s e t e m p e r a t u r e s a n d p r e ssures. 5,11,17,20,[24][25][26][27]36,39,44,47,51,83,90,98 In this section, the adsorption isotherm does not involve electrostatic interaction as CH 4 has no dipole or quadrupole moment, and consequently, the electrostatic potential has a negligible contribution to the interaction between CH 4 and a perfect graphene surface, while CO 2 exhibits the opposite behavior owing to its quadrupole moment. 25,47,55 This section focuses mainly on the van der Waals potential between molecules.…”

Section: Simulation Resultsmentioning

confidence: 99%

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Simulation of Adsorption–Desorption Behavior in Coal Seam Gas Reservoirs at the Molecular Level: A Comprehensive Review

Wang

Chen

et al. 2020

Energy Fuels

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This work reviews the processes of methane (CH4) and carbon dioxide (CO2) adsorption and desorption, as well as the displacement of CH4 by CO2, at the molecular level. For the adsorbate, laboratory experiments and numerical simulations have been carried out to examine the adsorption and desorption behavior of CH4 and CO2. For the adsorbent, graphite, graphene, carbon nanotube, and heteroatom-containing carbon-based models have been developed for adsorption and desorption processes. In recent decades, simulations of carbon dioxide enhanced coalbed methane (CO2-ECBM) have achieved significant progress. This success has generated significant interest among the scientific communities, as coalbed methane is one of the cleanest forms of energy. Furthermore, an improved understanding of this process can help to sequester CO2 in deep unminable coal seam gas reservoirs to mitigate CO2 emission. This work reviews the advantages and weaknesses of three simulation methods, namely, molecular dynamics (MD), Monte Carlo (MC), and the density functional theory (DFT), with respect to their applications in CO2-ECBM and CO2 sequestration in CBM. Based on such simulations, dynamic and thermodynamic properties have been analyzed to evaluate the effectiveness of CO2-ECBM and CO2 sequestration. In recent studies, MD simulation has been commonly used to optimize the configuration of the adsorbate and adsorbent, as well as to define the self-diffusion coefficient and mean squared distance. However, this approach only works for a small atomic system or a short time simulation process. MC, on the other hand, is used to predict the adsorption behavior of pure component and binary and ternary mixtures of adsorbates. Nevertheless, the simulation cannot obtain information on the dynamic processes. Meanwhile, DFT is commonly used to predict the adsorption site, orientation, and adsorption energy. Dynamic and thermodynamic properties are discussed based on the three simulation methods. Certain aspects facing the future are also addressed.

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Section: Simulation Resultsmentioning

confidence: 98%

“…The adsorption isotherm is a criterion used to examine the adsorption capacity of a gas under diverse temperatures and pressures. ,,,,− ,,,,,,,, …”

Section: Simulation Resultsmentioning

confidence: 99%

Section: Simulation Resultsmentioning

confidence: 99%

Section: Simulation Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Simulation of Adsorption–Desorption Behavior in Coal Seam Gas Reservoirs at the Molecular Level: A Comprehensive Review

Wang

Chen

et al. 2020

Energy Fuels

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“…Coal is a stable absorbent; as a natural reservoir, it has a great gas adsorption capacity. Many theoretical and experimental studies on the adsorption gas content of coal have been reported [2][3][4]. For example, Lu et al [5] performed the isothermal methane adsorption experiments and studied the supercritical methane adsorption characteristics of middlerank tectonically deformed coals (TDCs) from the Huaibei coalfield, and the mechanism of methane adsorption in TDCs was explored.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Characteristics of Methane Adsorption of Coal with Different Initial Gas Pressures at Different Temperatures

Cai

Feng

Jiang

et al. 2019

Advances in Materials Science and Engineering

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The adsorption of methane in coal depends on both pressure and temperature, and the adsorption gas content decreases as the temperature rises while increases as the pressure increases. When the gas molecule switches between the free state and adsorbed state, energy exchange is accompanied. To study the thermodynamic characteristics (adsorption heat, adsorption content, and adsorption time) of the methane adsorption of coal, the isothermal methane adsorption experiments of coal with different initial free gas pressures at different temperatures (30–90°C) were conducted. In this paper, a well-defined mathematical function of the adsorption heat was established on the basis of the actual gas state equation, Boltzmann energy distribution theory, and the two-state energy model, and the function was verified by the experimental data. The results show that the mathematical function of the adsorption heat can well describe the relationship among the adsorption heat, temperature, and initial free gas pressure in the closed adsorption system, and the adsorption heat involves the initial free gas pressure. The greater the initial free gas pressure, the less the adsorption heat is. In the adsorption process with different initial free gas pressures at different temperatures, the real-time free gas content increases with time and the adsorption system shows desorption process generally. For the adsorption process with the same initial free gas pressure, the adsorption time increases with the rising temperature. For the adsorption process with different initial free gas pressures at the same temperature, the greater the initial free gas pressure, the shorter the adsorption time it takes to reach an equilibrium state. The results help to understand the thermodynamic characteristics and the heat and mass transfer of methane in coal adsorption.

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Computer simulation of coal organic mass structure and its sorption properties

Zhuravlev

Porokhnov

2019

Int J Coal Sci Technol

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Structural model of C 100 H 79 O 7 NS coal organic mass was obtained within density functional theory in the localized orbital basis set using the B3LYP hybrid functional. The model was compared with the known experimental data for coal of different grades and its sorption properties were studied with respect to CH 4 , CO 2 and H 2 O. It has been shown that macromolecule of coal organic mass has bulk structure with a pore inside it. Interaction between coal and CH 4 molecules consists of typical physical adsorption with oligomer formation on the pore border, physical adsorption with elements of chemical adsorption was also observed between coal and H 2 O molecules. Interaction between coal and H 2 O molecules included both physical and chemical adsorbion.

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Molecular Simulation of H2O, CO2, and CH4 Adsorption in Coal Micropores

Cited by 12 publications

References 12 publications

Simulation of Adsorption–Desorption Behavior in Coal Seam Gas Reservoirs at the Molecular Level: A Comprehensive Review

Simulation of Adsorption–Desorption Behavior in Coal Seam Gas Reservoirs at the Molecular Level: A Comprehensive Review

Thermodynamic Characteristics of Methane Adsorption of Coal with Different Initial Gas Pressures at Different Temperatures

Computer simulation of coal organic mass structure and its sorption properties

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