A study on the FTIR spectra of pre- and post-explosion coal dust to evaluate the effect of functional groups on dust explosion

Lin, Song; Liu, Zhentang; Zhao, Erfeng; Qian, Jiansheng; Li, Xiaoliang; Zhang, Qiming; Ali, Muhammad

doi:10.1016/j.psep.2019.07.018

Cited by 57 publications

(20 citation statements)

References 36 publications

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“…FT-IR spectra can be obtained to derive molecular structure information by analysis of the position and intensity of absorption peaks of different functional groups. 60 The basic structural units in coal, such as alkyl side chains, oxygen-containing groups, or aromatic rings, can be analyzed in detail on the basis of changes in the absorption peak intensity. To determine changes in the characteristic absorption peaks in the infrared spectrum after ScCO 2 injection with different pressures, the FT-IR spectrogram is divided into four parts: (1) hydroxyl groups (−OH, 3700–3100 cm –1 ), (2) aliphatic structures (−CH X , 3000–2800 cm –1 ), (3) aromatic structures (1600 cm –1 ), and (4) aromatic out-of-plane structures (−C–H–, 900–700 cm –1 ); the FT-IR spectra of the functional-group region are shown in Figure 12 .…”

Section: Resultsmentioning

confidence: 99%

Swelling Characteristics and Interaction Mechanism of High-Rank Coal during CO₂ Injection: A Molecular Simulation Study

Dong

Zhai²,

Jia

2022

ACS Omega

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In CO 2 -enhanced coalbed methane (CO 2 -ECBM) engineering, accurate knowledge of the interaction mechanism of CO 2 and coal matrix is crucial for improving the recovery of CH 4 and contributing to the geological sequestration of CO 2 . This study is performed to prove the accuracy of molecular simulation and calculate the variation characteristics of pore structure, volumetric strain, mechanical properties, Fourier transform infrared (FT-IR) spectra, and the system free energy by molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) methods. According to the obtained results, a relationship between pore structure, swelling strain, mechanical properties, chemical structure, and surface free energy was established. Then, the correlation of various coal change characteristics was analyzed to elucidate the interaction mechanism between CO 2 and coal. The results showed that (1) the molecular simulation method was able to estimate the swelling mechanism of CO 2 and coal. However, because the adsorption capacity of the molecular simulate is greater than that of the experiment and the raw coal is softer than the macromolecular structure, the molecular results are slightly better than the experimental results. (2) As pressure increased from 0 to 4 MPa, the intramolecular pores and sorption-induced strain changed significantly, whereas when the pressure increased from 4 to 8 MPa (especially at 6–8 Mpa), there was an increase of the intermolecular pores and mechanical properties and transition from elastic to plastic. In addition, when the pressure was >8 MPa, the coal matrix changed slightly. ScCO 2 with a higher adsorption capacity results in greater damage and causes larger alterations of coal mechanical properties. (3) The change of the coal matrix is essentially controlled by the surface free energy of the molecular system. E valence affects the aromatic structure and changes the volume of the intramolecular pores, thus affecting the sorption-induced strain change rate. E non affects the length of side chains and the disorder degree of coal molecules and changes the volume of the intramolecular pores, thus affecting the mechanical property change rate. Our findings shed light on the dynamic process of coal swelling and provide a theoretical basis for CO 2 enhancing the recovery of CH 4 gas in coal.

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Section: Resultsmentioning

confidence: 99%

Swelling Characteristics and Interaction Mechanism of High-Rank Coal during CO₂ Injection: A Molecular Simulation Study

Dong

Zhai²,

Jia

2022

ACS Omega

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“…In the FTIR spectra before and after coal dust explosion ( Figure 9 ), the vibration peaks of the chemical structure in the lignite specimen mainly occurred at 1600–600, 3000–2280, and 3700–3300 cm –1 . 43 The functional groups mainly consisted of the C–H bonds in olefins and in aromatic hydrocarbons as well as hydroxyl groups. The peaks at 1700–1510 cm –1 corresponded to the vibration of the C=C bonds in the aromatic hydrocarbon.…”

Section: Resultsmentioning

confidence: 99%

The Performance and Mechanism of the Green Explosion Suppressant SGA for Coal Dust Explosion Suppression

et al. 2021

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In recent years, coal processing is developing rapidly, but there are often hidden safety hazards such as coal dust explosions during coal processing. In order to ensure safe production and avoid coal dust explosion accidents, a carrier with unique micro-mesoporous structure (SG) based waste molecular sieves was prepared. After that, the carrier was loaded with (NH 4 ) 2 C 2 O 4 (A) uniformly by ultrasound, which acted as an activity component for the first time. A novel micro-mesoporous coal dust explosion suppressant (SGA) is obtained. The law influence of different compositions of suppressant on the flame propagation of explosion was investigated. The results showed that the best ratio of waste molecular sieve, zirconium dioxide, and (NH 4 ) 2 C 2 O 4 of the suppressant is 1:7:2. The suppression performance increases with the increase of the addition of suppressant. When the addition amount is 70 wt %, the explosion loses the ability to continue to expand. Finally, combining the suppression performance with characterization results, the physical and chemical synergistic suppression mechanism is proposed, which reveals the reason why the suppressant has efficient suppression performance. The study could realize the green reuse of waste molecular sieves and provide guarantees for safe production of the coal processing industry.

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“…20,31 The peak absorption positions of functional groups in the original infrared spectra overlap, meaning that the peak position of each functional group cannot be clearly identified, so it is necessary to analyze the spectrum through peak fitting. [32][33][34][35][36] The deconvolution method was used here as it is the best method for the analysis of the peak absorption positions. 25,37 In order to carry out this analysis, the infrared spectrum's overlapping bands were processed using the deconvolution method; the spectrum's positions and number were obtained through the spectrum's second derivative 38 ; and the data processing software Peakfit V4.12 (SeaSolve Software, San Jose, CA) was used to analyze the FTIR spectrum's peak separation and curve fitting.…”

Section: Curve-fitting Analysis Of Ftir Spectramentioning

confidence: 99%

The evolution law of functional groups during the heating of coal in oxygen and oxygen‐free atmospheres

et al. 2021

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There is a change in both the quantity and type of functional groups due to the fact that they become oxidized and pyrolyzed during the spontaneous coal combustion process. In order to study the oxidation and pyrolysis mechanisms that are at play during the evolution of these functional groups, in situ Fourier transform infrared (FTIR) spectroscopy was employed to test the real-time evolution of these functional groups in both air and argon atmospheres. The differences found between functional groups when under an oxygen oxygen-free environment were analyzed. The results show that when the temperature exceeds 200°C, the changes in functional groups steadily increase and that regardless of whether the atmosphere is made up of argon or air, the oxygen-containing functional groups change significantly. In this situation, −OH, −CH 3 , and −CH 2 -are important reactants in the whole heating process; −COOH and −C=O are reactants during the low temperature oxidation stage, but when reaching the high temperature stage, they become the products; C-O-C and C=C is a stable reaction product. During the coal spontaneous combustion process, oxidation and pyrolysis work as two coupling reactions: The heat released by the oxidation reaction pyrolyzes the macromolecular structure and coal-oxygen complexes, while a large number of active groups are produced during pyrolysis, which then provides the reactants for the oxidation reaction. These results reveal the changes that functional groups go through during the process of oxidation and pyrolysis, and provide a theoretical basis for the development of efficient fire-fighting materials.

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A study on the FTIR spectra of pre- and post-explosion coal dust to evaluate the effect of functional groups on dust explosion

Cited by 57 publications

References 36 publications

Swelling Characteristics and Interaction Mechanism of High-Rank Coal during CO₂ Injection: A Molecular Simulation Study

Swelling Characteristics and Interaction Mechanism of High-Rank Coal during CO₂ Injection: A Molecular Simulation Study

The Performance and Mechanism of the Green Explosion Suppressant SGA for Coal Dust Explosion Suppression

The evolution law of functional groups during the heating of coal in oxygen and oxygen‐free atmospheres

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A study on the FTIR spectra of pre- and post-explosion coal dust to evaluate the effect of functional groups on dust explosion

Cited by 57 publications

References 36 publications

Swelling Characteristics and Interaction Mechanism of High-Rank Coal during CO2 Injection: A Molecular Simulation Study

Swelling Characteristics and Interaction Mechanism of High-Rank Coal during CO2 Injection: A Molecular Simulation Study

The Performance and Mechanism of the Green Explosion Suppressant SGA for Coal Dust Explosion Suppression

The evolution law of functional groups during the heating of coal in oxygen and oxygen‐free atmospheres

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Swelling Characteristics and Interaction Mechanism of High-Rank Coal during CO₂ Injection: A Molecular Simulation Study

Swelling Characteristics and Interaction Mechanism of High-Rank Coal during CO₂ Injection: A Molecular Simulation Study