Effects of flammable gases on the explosion characteristics of CH 4 in air

Wang, Tao; Luo, Zhenmin; Wen, Hu; Cheng, Fangqin; Deng, Jun; Zhao, Jingyu; Guo, Zhengchao; Lin, Jingjing; Kang, Kai; Wang, Weifeng

doi:10.1016/j.jlp.2017.06.018

Cited by 36 publications

(8 citation statements)

References 37 publications

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“…For example, Qi et al 49 and Zhang et al 36 divided the combustion behaviour for premixed methane-hydrogen into three modes. Wang et al 40 and Luo et al 48 also found similar laws in the combustion of a mixed gas of methane, ethylene, and ethane. Also found similar laws for the combustion of a mixed gas of methane, ethylene, and ethane.…”

Section: Resultsmentioning

confidence: 71%

“…Due to the influence of the added gas, the proportion of air decreases, and the added gas will compete with methane to consume oxygen. Moreover, it has been found that the LEL of methane decreases more significantly relative to the UEL 26 , 40 . The explosion limit range for methane showed a linear upward trend, which was 13.3% larger than the explosion range for pure methane gas.…”

Section: Resultsmentioning

confidence: 99%

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Influence of acetylene on methane–air explosion characteristics in a confined chamber

Jia

Zhu

Niu³

et al. 2021

Sci Rep

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To study the impact of acetylene on methane explosions, the safe operation of coal mines should be ensured. In this paper, a 20 L spherical tank was used to study the explosive characteristics of acetylene–methane–air mixture. In addition, the GRI-Mech3.0 mechanism was used to study the chemical kinetic mechanism for the mixed gas, and the effect of adding acetylene on the sensitivity of methane and the yield of free radicals was analysed. The results show that acetylene can expand the scope for methane explosion, lower the lower explosion limit, and increase the risk of explosion. Acetylene increases the maximum explosion pressure, laminar combustion rate and maximum pressure rise rate for the methane–air mixture while shortening the combustion time. Three combustion modes for the acetylene–methane–air mixture were determined: methane-dominated, transitional and acetylene-dominated combustion modes. Chemical kinetic analysis for the mixed gas shows that as the volume fraction of acetylene increases, the generation rate for key free radicals (H*, O* and OH*) gradually increases, thereby increasing the intensity of the explosive reaction. The results from this research will help formulate measures to prevent coal mine explosion accidents.

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Section: Resultsmentioning

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Influence of acetylene on methane–air explosion characteristics in a confined chamber

Jia

Zhu

Niu³

et al. 2021

Sci Rep

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“…The gas explosion risk ( F ) based on the explosion range can be calculated by eq , which indicates the possibility of a gas explosion. Its value F is defined as F = false( L · U false) 1 / 2 − L ( L · U ) 1 / 2 where U and L are the upper and lower explosion limits, respectively. The F values range from 0 to 1.…”

Section: Experimental Results and Analysismentioning

confidence: 99%

Secondary Explosion Characteristics and Chemical Kinetics of CH₄/Air Induced by a High-Temperature Surface

Wang,

Zhang,

Wei

et al. 2023

ACS Chem. Health Saf.

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The gas explosion induced by the high-temperature surface of coal spontaneous combustion in goaf will cause a devastating blow to personnel and equipment in the process of coal mining. Secondary explosion may be induced by the high-temperature surface of coal spontaneous combustion after primary explosion with the continuous emission of gas and the ventilation of goaf. This will lead to new disasters for the ongoingrescue operation. A high-temperature source explosion experimental system consistent with the similarity and unity of goaf was designed and developed based on the similarity criterion in this study. A CH4/air explosion experiment was carried out with the high-temperature surface as an ignition source. The characteristics of secondary explosion were studied, and chemical kinetics was analyzed. It is of great significance to the safety of the process of mining production. The results show that the secondary explosion limit (6.5–14%) is less than the primary explosion (5.5–14.5%). Its explosion risk (F) is reduced by 15.6%. The key parameters P max, T max, and (dP /dt)max of secondary explosion at each concentration are lower than those of primary explosion. The t e of secondary explosion is higher than primary explosion. The most dangerous concentration of primary and secondary explosions induced by the high-temperature surface is 11.5%. Carbon oxides (CO2 and CO) and C2 hydrocarbon gases (C2H2, C2H4, and C2H6) are generated after primary explosion. The chemical kinetics of secondary explosion was analyzed with CHEMKIN Pro 2021. When the CH4 concentration is <11.5%, the formation of the key free radicals ·H, ·O, ·OH, and CH2O is inhibited due to the formation of CO2. When the CH4 concentration is ≥11.5%, the formation of the key free radicals ·H, ·O, ·OH, and CH2O is inhibited due to the generation of combustible gases (C2H2, C2H4, C2H6, and CO) and inert gas (CO2). As a result, the limit range of secondary explosion and the explosion hazard characteristics are reduced. R156 and R158 played major roles in the process of secondary explosion with the analysis of reaction sensitivity.

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“…In recent years, much research has been performed on determining flammability and explosion parameters, such as flammable limits, − explosion pressure and maximum rate of pressure rise, − minimum ignition energy, − , propagation behaviors, − and limiting oxygen concentration in gas mixtures. − Additionally, researchers have investigated the inerting effect of the addition of water mist and inert gases, such as nitrogen, carbon dioxide, helium, and argon, on flammable gas mixture explosions. , The abovementioned studies have provided a reliable reference for the prevention of gas explosions at the macroscopic level. Similarly, it is necessary to study the micromechanism of combustible gas mixtures to better understand gas explosions and to fundamentally prevent explosions.…”

Section: Introductionmentioning

confidence: 99%

Micromechanism of the Initiation of a Multiple Flammable Gas Explosion

Luo

et al. 2019

Energy Fuels

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To investigate the micromechanism of a multiple flammable gas explosion, CH 4 , CO, C 2 H 6 , C 2 H 4 , and H 2 were selected to determine the thermodynamic and dynamic characteristics of the gas mixture explosion using Gaussian software. The initiation mechanism and primary initiation pathway of the joint explosion of the five combustible gases were analyzed. A spherical experimental device for gas/dust explosions combined with a system for spectral measurements was implemented to obtain emission spectra of the • H radical and CH 2 O during the gas mixture explosion process. The oxidation reaction of CH 4 initiated the chain reaction for the entire explosive reaction rather than the CO/C 2 H 6 /C 2 H 4 /H 2 mixture at the ignition moment of the explosion. Nevertheless, addition of the CO/C 2 H 6 /C 2 H 4 /H 2 mixture had obvious effects on the chain-branching reactions of the CH 4 explosion. The • CH 3 radicals produced during methane oxidation induced a hydrogen reaction, and • H radicals generated in the reaction of • CH 3 and H 2 triggered the involvement of other combustible gases in the explosion reaction, which considerably decreased the activation energy demand by multiple combustible gases to participate in the explosion reaction. The sequence of flammable gases involved in the explosion reaction was CH 4 , H 2 , CO, C 2 H 4 , and C 2 H 6 . Furthermore, the experimental results indicated that the • H radical appeared before CH 2 O during the explosion reaction process, which was consistent with the numerical simulation results. Moreover, the numerical simulation results provided a theoretical basis for the prevention of gas explosions and process safety in the petrochemical and mine industries.

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Effects of flammable gases on the explosion characteristics of CH 4 in air

Cited by 36 publications

References 37 publications

Influence of acetylene on methane–air explosion characteristics in a confined chamber

Influence of acetylene on methane–air explosion characteristics in a confined chamber

Secondary Explosion Characteristics and Chemical Kinetics of CH₄/Air Induced by a High-Temperature Surface

Micromechanism of the Initiation of a Multiple Flammable Gas Explosion

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Effects of flammable gases on the explosion characteristics of CH 4 in air

Cited by 36 publications

References 37 publications

Influence of acetylene on methane–air explosion characteristics in a confined chamber

Influence of acetylene on methane–air explosion characteristics in a confined chamber

Secondary Explosion Characteristics and Chemical Kinetics of CH4/Air Induced by a High-Temperature Surface

Micromechanism of the Initiation of a Multiple Flammable Gas Explosion

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Secondary Explosion Characteristics and Chemical Kinetics of CH₄/Air Induced by a High-Temperature Surface