Comparative study on methane/air deflagration with hydrogen and ethane additions: Investigation from macro and micro perspectives

Su, Bin; Luo, Zhenmin; Deng, Jun; Wang, Tao; Liu, Litao; Zhou, Shengyuan; Lu, Kunlun; Zhang, Jiang; Liu, Lu

doi:10.1016/j.psep.2023.04.030

Cited by 29 publications

(5 citation statements)

References 75 publications

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“…This indicates that the deflagration consequences of CH 4 /H 2 mixtures with low hydrogen blending ratios are more severe under fuel-lean conditions, while those with high hydrogen blending ratios are more severe under fuel-rich conditions. The continuous addition of H 2 provides CH 4 /H 2 mixtures with more high-energy free radicals such as H, OH, and O, , so the improvement of the flame combustion rate by H 2 is essentially dominated by the chemical reaction rate. However, the influence of CH 4 on the flame combustion rate is mainly through the thermal effect, as the heat generated during CH 4 combustion is higher than that of H 2 .…”

Section: Resultsmentioning

confidence: 99%

Effects of Hydrogen Blending Ratio and Equivalence Ratio on the Dynamic Characteristics of Deflagration Shock Waves of CH₄/H₂ Mixtures

Liu,

Peng

et al. 2024

ACS Omega

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To evaluate the explosion hazard of CH4/H2 mixtures, experiments were conducted in a long and closed pipeline with a length-to-diameter ratio of 51 and built-in obstacles, and the characteristic parameters of deflagration shock waves were analyzed under different hydrogen blending ratios (0 ≤ λ ≤ 100%) and equivalence ratios (0.5 ≤ Φ ≤ 3). The results indicate that within the range of Φ = 0.8–1.2, the explosion overpressure (P P) exhibits a “two-zone” structure distribution. When 0 ≤ λ ≤ 80%, P P shows an initial increase and then a decrease in both regions, while deflagration to detonation transition (DDT) occurs in the second evolution region when λ = 100%, which is caused by the different strengths of the positive feedback mechanism coupled with flames and shock waves. The P max, (dP/dt)max, and V a show a trend of first increasing and then decreasing and monotonically increasing with the increase of the equivalence ratio and hydrogen blending ratio, respectively, and reach their maximum values at Φ = 1.0 and λ = 100%. For CH4/H2 mixtures with low hydrogen blending ratios (λ = 0 and 20%), the P max and (dP/dt)max in the fuel-lean conditions (Φ = 0.9 and 0.8) are higher than those in the fuel-rich conditions (Φ = 1.1 and 1.2), while the CH4/H2 mixtures under high hydrogen blending ratios (λ = 80 and 100%) are the opposite. Overall, the increase in H2 at a high hydrogen blending ratio and the increase in the equivalence ratio at a fuel-lean condition significantly enhance the average V a. In addition, chemical kinetics analysis found that R38 and R52 elementary reactions are the dominant elementary reactions that promote and inhibit temperature increase, respectively. Their temperature sensitivity coefficients are negatively correlated with the hydrogen blending ratio and positively correlated with the equivalence ratio. The research results provide vital information for evaluating the explosion hazards of CH4/H2 mixtures and developing safety protection measures.

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Section: Resultsmentioning

confidence: 99%

Effects of Hydrogen Blending Ratio and Equivalence Ratio on the Dynamic Characteristics of Deflagration Shock Waves of CH₄/H₂ Mixtures

Liu,

Peng

et al. 2024

ACS Omega

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“…However, hydrogen has a wide flammability limit (about 4−75% by volume), exceedingly low ignition energy (minimum value of 0.019 mJ), is extremely leaky and brittle, and is highly susceptible to accidental fires and explosions. 7,8 In recent years, researchers have conducted extensive basic research on hydrogen safety, including ignition limits, ignition locations, initial conditions, and shock waves. 9−14 Zhang et al 15,16 developed an explosion limit model for combustible gas mixtures and made predictions theoretically.…”

Section: Introductionmentioning

confidence: 99%

“…Hydrogen can be used in both engines and fuel cells, especially in hydrogen fuel cell vehicles, which are an excellent system for utilizing hydrogen as fuel cells produce only water and are highly energy efficient. However, hydrogen has a wide flammability limit (about 4–75% by volume), exceedingly low ignition energy (minimum value of 0.019 mJ), is extremely leaky and brittle, and is highly susceptible to accidental fires and explosions. , …”

Section: Introductionmentioning

confidence: 99%

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Effect of N₂ and CO₂ on the Explosion Properties of High Equivalence Ratios of Hydrogen

Luo,

Qi,

et al. 2023

ACS Omega

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The explosion characteristics of premixed gases under different equivalence ratios (1.0–3.0) and inert gas addition (5–20%) are experimentally investigated, and sensitivity analysis of the radical reactions is carried out using the USC Mech II model to analyze the molar fraction of radicals. The results show that at high equivalence ratios, inert gas has little effect on flame stability. The addition of an inert gas reduces the tensile rate in the early stage of flame growth. At high equivalence ratios, CO 2 inhibits explosive flame propagation twice as effectively as N 2 . Due to the large heat capacity and chemical kinetic effects, CO 2 has a stronger inhibitory effect on the explosion pressure than N 2 , and the inhibition efficiency on the explosion strength is nearly twice that high. To further analyze the effect of different inert gas addition ratios on chemical kinetics, sensitivity analysis, and molar fraction simulations were performed. The thermal and chemical kinetic effects of CO 2 cause later generation of H and OH radicals and the partial chain reaction involving CO 2 causes a lower peak of H radicals than the peak of H radicals generated under an N 2 atmosphere. However, CO 2 is a direct reactant and the third body to produce a small chemical kinetic effect.

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“…Scholars have widely investigated leakage diffusion of combustible gas and quantified gas concentration distributions and hazard areas of H 2 , 4-6 liquefied petroleum gas, 7 and liquefied natural gas (LNG) [8][9][10][11][12][13] using PHAST, ALOHA, FLUENT, FLACS, and computational fluid dynamics (CFD) software. The influences of wind conditions, 14,15 aperture, 16,17 and obstacles 18,19 on gas leakage diffusion have mainly been studied in terms of the influencing factors, and the obtained results could provide an important basis to resolve accidents and mitigate pollution hazards.…”

Section: Introductionmentioning

confidence: 99%

Consequence analysis of CNG leakage at joint refueling and charging stations

Luo

Liu

et al. 2023

Process Safety Progress

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The number of new‐energy vehicles is steadily increasing worldwide, and joint refueling and charging stations will be increasingly constructed and developed in China. A CNG leakage at joint stations can lead to superimposed consequences, including fire (flash fire, pool fire, jet fire), explosion, and release of toxic and hazardous gases. Based on FLACS and SAFETI, the impact of leakage aperture and wind direction on CNG leakage diffusion are analyzed by modeling a joint refueling and charging station in Shaanxi, China. The safe distance between charging piles and leakage points is investigated in the worst case scenario. The superimposed consequences of leakage in joint stations under different scenarios are analyzed, and the individual risk is analyzed at stations. This study shows that the larger the leakage aperture, the larger the CNG leakage dispersion range under the same wind directions and wind speeds, and the higher the wind speed, the more volatile the gas under the same leakage apertures. The safety distance of the charging pile should reach at least 37 and 40 m considering leaks in the tanker and gas storage well, respectively. The impact range of superimposed consequences shows the descending order of jet fire > flash fire > pool fire.

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Comparative study on methane/air deflagration with hydrogen and ethane additions: Investigation from macro and micro perspectives

Cited by 29 publications

References 75 publications

Effects of Hydrogen Blending Ratio and Equivalence Ratio on the Dynamic Characteristics of Deflagration Shock Waves of CH₄/H₂ Mixtures

Effects of Hydrogen Blending Ratio and Equivalence Ratio on the Dynamic Characteristics of Deflagration Shock Waves of CH₄/H₂ Mixtures

Effect of N₂ and CO₂ on the Explosion Properties of High Equivalence Ratios of Hydrogen

Consequence analysis of CNG leakage at joint refueling and charging stations

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Comparative study on methane/air deflagration with hydrogen and ethane additions: Investigation from macro and micro perspectives

Cited by 29 publications

References 75 publications

Effects of Hydrogen Blending Ratio and Equivalence Ratio on the Dynamic Characteristics of Deflagration Shock Waves of CH4/H2 Mixtures

Effects of Hydrogen Blending Ratio and Equivalence Ratio on the Dynamic Characteristics of Deflagration Shock Waves of CH4/H2 Mixtures

Effect of N2 and CO2 on the Explosion Properties of High Equivalence Ratios of Hydrogen

Consequence analysis of CNG leakage at joint refueling and charging stations

Contact Info

Product

Resources

About

Effects of Hydrogen Blending Ratio and Equivalence Ratio on the Dynamic Characteristics of Deflagration Shock Waves of CH₄/H₂ Mixtures

Effects of Hydrogen Blending Ratio and Equivalence Ratio on the Dynamic Characteristics of Deflagration Shock Waves of CH₄/H₂ Mixtures

Effect of N₂ and CO₂ on the Explosion Properties of High Equivalence Ratios of Hydrogen