Molecular simulation of C2H4/CO2/N2/O2 adsorption characteristics in lignite and anthracite

Zhang, Jing; Wang, Jiren; Zhang, Chunhua; Li, Zongxiang; Lü, Bing; Zhu, Jinchao

doi:10.1063/5.0057456

Cited by 10 publications

(10 citation statements)

References 48 publications

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“…The adsorption isotherms for different gases at different strains were obtained by the Langmuir formula. 38 The Langmuir fitting formula was as follows:…”

Section: Uniaxial Compression Simulation Methodmentioning

confidence: 99%

“…The simulation process was performed using COMPASS II force field at 298.15 K. The number of equilibrium steps was 100,000, the number of production steps was 1,000,000, and the average adsorption amount was calculated. The adsorption isotherms for different gases at different strains were obtained by the Langmuir formula . The Langmuir fitting formula was as follows: y = a b x / ( 1 + b x ) …”

Section: Simulation Methodologymentioning

confidence: 99%

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Molecular Simulation of the Pore Structure and Adsorption Properties of Coal under Compression Stress

2023

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The deformation of the macromolecular structure of coal under compression stress may affect the pore structure and adsorption properties. In this study, the Grand Canonical Monte Carlo and molecular dynamics methods were used to investigate the effects of compression stress on the pore structure and adsorption properties of coal, and the coupling relationships between stress, strain, pore structure, and adsorption properties were explored. A macromolecular model of coal was constructed, and uniaxial compression simulation was conducted. The increase of compression stress reduces the pore volume, specific surface area, and connectivity of coal and concentrates the pore size distribution in pores with smaller sizes. The increase of stress leads to a different degree of reduction in the adsorption performance of coal on CH 4 and CO 2 , and the stress sensitivity of CH 4 is slightly stronger than that of CO 2 . The results of adsorption configurations in the pores under different strains indicate that the reduction of adsorption properties is controlled by the pore volume and pore connectivity. The adsorption performance of CH 4 and CO 2 in coal at different strains has a good linear relationship with the volume and specific surface area of the pores; the smaller the volume and specific surface area of the pores, the weaker the adsorption performance of coal. This study clarifies the control of the strain response under compression stress on the pore structure and adsorption properties of coal and provides guidance for the study of adsorption, desorption, and diffusion of CBM.

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“…The adsorption isotherms for different gases at different strains were obtained by the Langmuir formula. 38 The Langmuir fitting formula was as follows:…”

Section: Uniaxial Compression Simulation Methodmentioning

confidence: 99%

Section: Simulation Methodologymentioning

confidence: 99%

Molecular Simulation of the Pore Structure and Adsorption Properties of Coal under Compression Stress

2023

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“…The parameter settings of geometry optimization, energy optimization, and annealing optimization are shown in Table 1. 28,29 2.2. AMS Molecular Dynamics Simulation.…”

Section: Modeling and Computational Detailsmentioning

confidence: 99%

“…Here, the Wiser model is appropriately modified to increase the proportion of oxygen-containing functional groups, focusing on the reaction direction of oxygen-containing functional groups and carbon functional groups. , Molecular dynamics simulation software was used to optimize the model. The parameter settings of geometry optimization, energy optimization, and annealing optimization are shown in Table . , …”

Section: Modeling and Computational Detailsmentioning

confidence: 99%

Molecular Dynamics Simulation and Gas Generation Tracking of Pyrolysis of Bituminous Coal

Zhang

Wang

et al. 2022

ACS Omega

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To study the generation rules of organic molecules or fragments and the generation paths of some hydrocarbon gases (C 2 H 2 /C 2 H 4 ) and inorganic gases (CO 2 /H 2 O/H 2 /H 2 S) in the pyrolysis process of bituminous coal at 1000–5000 K, the ReaxFF molecular dynamics module in AMS software was used to simulate the pyrolysis behavior of the Hongqingliang model, Gaojialiang model, and Wiser model. With the increase of temperature, the system potential energy decreases, the endothermic efficiency increases first and then decreases, the fragments of C 1 –C 4 fragments increase, and the gas molecules generated increase. In the pyrolysis process, the oxygen-containing functional groups and hydrogen groups formed H 2 O and H 2 with the increase of temperature. H 2 S as an intermediate product is always maintained in dynamic equilibrium. CO 2 comes from the decarboxylation of the carboxyl groups. When the temperature is lower than 3000 K, C 2 H 4 and C 2 H 2 are mainly formed by the adjacent carbon structure in coal molecules, and C 2 H 4 is formed from the ethyl side chain, the naphthenic structure, and the unstable aromatic rings. C 2 H 2 is formed from naphthene structures and aromatic rings with multiple side chains. When the temperature is higher than 3000 K, C 2 H 4 and C 2 H 2 are mainly formed by the random combination of free radicals generated by the crushing of coal molecules. The research results are of great significance to coal pyrolysis and clean utilization of coal.

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“…The structural units are connected by oxygen bridge and methylene bridge, and they also have side chain alkyl, hydroxyl, carboxyl, methoxyl and other groups. Macromolecules are cross-linked into a network-like structure in three-dimensional space, and some small molecules are connected to it by hydrogen bonds or van der Waals forces (Yang et al, 2015;Qu et al, 2018;Chen et al, 2021;Zhang et al, 2021). In the study of coal-based polymers and composites, it is very important to study the oxidation and spontaneous combustion characteristics of anthracite.…”

Section: Introductionmentioning

confidence: 99%

Study on the Change Law of Red-Green-Blue Values of Infrared Thermal Image in the Process of Anthracite Oxidation and Spontaneous Combustion

Wang

2022

Front. Mater.

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As the coal with the highest degree of coalification, anthracite is usually regarded as a mixture composed of organic and inorganic substances, with the characteristics of polymers and composites. It is very important to study the oxidation and spontaneous combustion characteristics of anthracite for the thermal properties of coal-based polymers and composites. Anthracite exhibits varying oxidation and spontaneous combustion characteristics at various stages of the oxidation and spontaneous combustion process, which cannot be fully demonstrated by the coal temperature alone. As a result, this paper develops an online method for characterizing the RGB values of infrared thermal images. The variation of the RGB value of an infrared thermal image during the oxidation and spontaneous combustion of anthracite was investigated. The findings show that there is a clear relationship between R (red), G (green), B (blue), RGB (red/green/blue) values, and coal temperature during the oxidation and spontaneous combustion of anthracite. The R and the G value curves each have one characteristic peak and two characteristic valleys in the experiment. However, the overall change range of the G value curve is relatively small; the B value curve has two characteristic peaks and one characteristic valley. There are no characteristic peaks and valleys in the RGB value curve, despite the influence of experimental instruments and the experimental environment.

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Molecular simulation of C2H4/CO2/N2/O2 adsorption characteristics in lignite and anthracite

Cited by 10 publications

References 48 publications

Molecular Simulation of the Pore Structure and Adsorption Properties of Coal under Compression Stress

Molecular Simulation of the Pore Structure and Adsorption Properties of Coal under Compression Stress

Molecular Dynamics Simulation and Gas Generation Tracking of Pyrolysis of Bituminous Coal

Study on the Change Law of Red-Green-Blue Values of Infrared Thermal Image in the Process of Anthracite Oxidation and Spontaneous Combustion

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