Assessment of flammability and explosion risks of natural gas-air mixtures at high pressure and high temperature

Huang, Lijuan; Pei, Shufeng; Wang, Yu; Zhang, Liang; Ren, Shaoran; Zhang, Zhe; Xiao, Yu

doi:10.1016/j.fuel.2019.03.023

Cited by 63 publications

(26 citation statements)

References 39 publications

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“…The flammable limit of the natural gas-air mixture at 20 MPa and 100 • C increased significantly from 4.95% to 15.51% at room temperature (0.1 MPa and 25 • C) to 2.87-64.40%. With the increase in pressure and temperature, the change in the upper flammable limit (UFL) was more sensitive than the change in the lower flammable limit (LFL) [15]. Within the temperature range of 25-100 • C, with the increase in the initial pressure, the UFL and LFL showed logarithmic growth and logarithmic decay, respectively, while the UFL and LFL increased linearly with the change in the initial temperature.…”

Section: Introductionmentioning

confidence: 96%

Oxidation and Characterization of Low-Concentration Gas in a High-Temperature Reactor

et al. 2020

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To achieve the efficient utilization of low-concentration mine gas, reduce resource waste and alleviate environmental pollution, the high-temperature oxidation of low-concentration gas at a concentration range of 1.00% to 1.50%, which is directly discharged into the atmosphere during coal mine production, was carried out to recover heat for reuse. The gas oxidation equipment was improved for the heating process and the safety of low-concentration gas oxidation under a high-temperature environment was evaluated. The experimental results showed that the reactor could provide a 1000 °C high-temperature oxidation environment for gas oxidation after installing high-temperature resistant ceramics. The pressure variation curves of the reactor with air and different concentrations of gas were similar. Due to the thermal expansion, the air pressure slightly increased and then returned to normal pressure. In contrast, the low-concentration gas exhibited a stable pressure response in the high-temperature environment of 1000 °C. The outlet pressure was significantly greater than the inlet pressure, and the pressure difference between the inlet and outlet exhibited a trend to increase with the gas concentration. The minimum pressure difference was 4 kPa (air) and the maximum was 11 kPa (1.50% gas). The explosion limit varied with the temperature and the blend of oxidation products. The ratio of measured gas pressure to air pressure after oxidation was below the explosion criterion, indicating that the measured concentration of gas is still safe after the shift of the explosion limit, which provides a safe concentration range for the efficient use of low-concentration gas in the future.

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Section: Introductionmentioning

confidence: 96%

Oxidation and Characterization of Low-Concentration Gas in a High-Temperature Reactor

et al. 2020

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“… 18 − 22 The experimental results show that the explosive limits of methane/natural gas can be significantly extended at high temperatures and high pressures, and the UEL is more sensitive than the LEL as pressure and temperature increase. 23 The peak explosion pressure is slightly reduced at high-temperature conditions and gradually increases with the initial pressure. 23 , 24 Moreover, many scholars have investigated the influence of initial ignition energy and initial turbulence on the explosion behavior of methane/air mixtures.…”

Section: Introductionmentioning

confidence: 97%

“… 23 The peak explosion pressure is slightly reduced at high-temperature conditions and gradually increases with the initial pressure. 23 , 24 Moreover, many scholars have investigated the influence of initial ignition energy and initial turbulence on the explosion behavior of methane/air mixtures. 16 , 17 , 25 , 26 The scholars proved that the level of initial ignition energy significantly impacts the flame and explosion characteristics and also extends the explosive limits of methane.…”

Section: Introductionmentioning

confidence: 97%

Experimental Investigation of the Impact of CO, C₂H₆, and H₂ on the Explosion Characteristics of CH₄

Chen

2020

ACS Omega

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Gas explosions are destructive disasters in coal mines. Coal mine gas is a multi-component gas mixture, with methane (CH 4 ) being the dominant constituent. Understanding the process and mechanism of mine gas explosions is of critical importance to the safety of mining operations. In this work, three flammable gases (CO, C 2 H 6 , and H 2 ) which are commonly present in coal mines were selected to explore how they affect a methane explosion. The explosion characteristics of the flammable gases were investigated in a 20 L spherical closed vessel. Experiments on binary- (CH 4 /CO, CH 4 /C 2 H 6 , and CH 4 /H 2 ) and multicomponent (CH 4 /CO/C 2 H 6 /H 2 ) mixtures indicated that the explosion of such mixtures is more dangerous and destructive than that of methane alone in air, as measured by the explosion pressure. Furthermore, a self-promoting microcirculation reaction network is proposed to help analyze the chemical reactions involved in the multicomponent (CH 4 /CO/C 2 H 6 /H 2 ) gas explosion. This work will contribute to a better understanding of the explosion mechanism of gas mixtures in coal mines and provide a useful reference for determining the safety limits in practice.

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“…The flammable limit of the natural gas-air mixture at 20 MPa and 100 ℃ increased significantly from 4.95%-15.51% at room temperature (0.1 MPa and 25 ℃) to 2.87% -64.40%. With the increase of pressure and temperature, the change of the upper flammable limit (UFL) was more sensitive than the change of the lower flammable limit (LFL) 15 . Within the temperature range of 25 ℃-100 ℃, with the increase of the initial pressure, UFL and LFL showed logarithmic growth and logarithmic decay, respectively, while the UFL and LFL increased linearly with the change of the initial temperature.…”

mentioning

confidence: 99%

“…The gas system was in an oxygen-depleted state near the upper flammable limit with a generation of CO during the production process. In contrast, the gas system was in an oxygen-rich state near the lower explosion limit, in which the reacted gases were almost all CO2 15 . With the increase of the initial temperature, the peak explosion pressure decreased while the heat release rate accelerated.…”

mentioning

confidence: 99%

Oxidation and Characterization of Low Concentration Gas in High-Temperature Reactor

Chen¹,

Wen²,

Yan³

et al. 2020

Preprint

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To achieve efficient utilization of low-concentration mine gas, reduce resource waste, and alleviate environmental pollution, high-temperature oxidation of low-concentration gas at a concentration range of 1.00% to 1.50% that is directly discharged into the atmosphere during coal mine production was oxidized to recover heat for reuse. The gas oxidation equipment was improved for the heating process, and the safety of low-concentration gas oxidation under high-temperature environment was evaluated. Experimental results showed that the reactor could provide a 1000 ℃ high-temperature oxidation environment for gas oxidation after installing high-temperature resistant ceramics. The pressure variation curves of the reactor with air and different concentrations of gas were similar. Due to the thermal expansion, the air pressure slightly increased and then returned to normal pressure. In contrast, the low-concentration gas exhibited a stable pressure response in the high-temperature environment of 1000 ℃. The outlet pressure was significantly greater than the inlet pressure, and the pressure difference between the inlet and outlet exhibited a trend to increase with the gas concentration. The explosion limit varied with the temperature and the blend with oxidation products. The ratio of measured gas pressure to air pressure after oxidation was below the explosion criterion, indicating that the measured concentration gas is still safe after the shift of explosion limit, which provides a safe concentration range for efficient use of low-concentration gas in the future.

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Assessment of flammability and explosion risks of natural gas-air mixtures at high pressure and high temperature

Cited by 63 publications

References 39 publications

Oxidation and Characterization of Low-Concentration Gas in a High-Temperature Reactor

Oxidation and Characterization of Low-Concentration Gas in a High-Temperature Reactor

Experimental Investigation of the Impact of CO, C₂H₆, and H₂ on the Explosion Characteristics of CH₄

Oxidation and Characterization of Low Concentration Gas in High-Temperature Reactor

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Assessment of flammability and explosion risks of natural gas-air mixtures at high pressure and high temperature

Cited by 63 publications

References 39 publications

Oxidation and Characterization of Low-Concentration Gas in a High-Temperature Reactor

Oxidation and Characterization of Low-Concentration Gas in a High-Temperature Reactor

Experimental Investigation of the Impact of CO, C2H6, and H2 on the Explosion Characteristics of CH4

Oxidation and Characterization of Low Concentration Gas in High-Temperature Reactor

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Experimental Investigation of the Impact of CO, C₂H₆, and H₂ on the Explosion Characteristics of CH₄