Flammability limits, limiting oxygen concentration and minimum inert gas/combustible ratio of H2/CO/N2/air mixtures

Schoor, Filip Van den; Norman, Frederik; Vandermeiren, K.; Verplaetsen, Filip; Berghmans, Jan; Bulck, Eric Van den

doi:10.1016/j.ijhydene.2008.12.038

Cited by 41 publications

(24 citation statements)

References 7 publications

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“…Consequently, the upward velocity increases slightly with pressure. Since a higher upward velocity leads to a higher flame stretch rate K , the slight increase of v and, hence, of the flame stretch rate K with pressure cause a slight decay in the flame propagation . Another explanation for the increase of the lower flammability limit with an increase in pressure is due to heat loss due to convection, which is greater at high pressures than at low, as density differences become greater .…”

Section: Resultsmentioning

confidence: 99%

“…Tschirschwitz et al studied the flammability limits of methane/air and hydrogen/air mixtures, for pressures up to 175 bar and temperatures up to 150 °C . Van den Schoor has actively researched the influence of pressure and temperature on flammability limits, including a study on the upper explosion limit of lower alkanes and alkenes at elevated pressure up to 30 bar and temperature up to 250 °C (2006), as well as the determination of flammability limits of hydrogen/carbon monoxide/nitrogen/air mixtures at temperatures up to 200 °C (2009). , …”

Section: Introductionmentioning

confidence: 99%

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Lean Flammability Limits of Syngas/Air Mixtures at Elevated Temperatures and Pressures

2018

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New experimental results for lean flammability limits (LFLs) of syngas/air (H2/CO/air) mixtures have been obtained at temperatures up to 200 °C and pressures up to 9 bar. ASTM Standard E918 (1983) provided the framework for tests at these elevated conditions, using a 1-L pressure-rated test cylinder in which the fuel–air mixtures were prepared and then ignited. The purpose for characterizing the flammability limits for these gaseous mixtures is to facilitate development of appropriate procedures for the safe industrial use of syngas, which contains large quantities of hydrogen and carbon monoxide gas. The LFLs for each gas mixture are found to decrease linearly with increasing temperature at all test pressures. The LFL results at atmospheric pressure are consistent with previous flammability studies, while those at elevated pressures represent new flammability data. An increase in the initial test pressure results in an increase of the LFLs for each test mixture, which also serves to address the lack of syngas/air flammability data at elevated pressures. An empirical formula is derived that allows for the calculation of the LFLs of all syngas/air test mixtures in the temperature and pressure range of the current study in an effort to promote the ease of use in practical applications. Predicted LFL values obtained using Le Chatelier’s mixing rule and an appropriate choice for the lower flammability limit of pure carbon monoxide are consistent with the experimentally determined values near ambient conditions of temperature and pressure.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lean Flammability Limits of Syngas/Air Mixtures at Elevated Temperatures and Pressures

2018

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“…This ratio is called the flammability limit. The flammability limit of the CO/H2/N2/air mixture compared in the presence of limited oxygen [3], the highest flammability limits of hydrocarbons diluted with inert gas [4], and the explosion behaviour of the hydrogen-enriched natural gas mixture have been investigated [5]. It is understood that the air mixture required for the explosion of each explosive chemical is different.…”

Section: Introductionmentioning

confidence: 99%

The Risk Calculation of Hazardous Zones Created By Flammable And Explosive Chemicals, LPG Tank Example

Büyükkıdan

Gümüş

USLU

2021

Academic Platform Journal of Natural Hazards and Disaster Management

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The determining of hazardous areas created by flammable and explosive chemicals is important to obtain a safe working environment. Taking precautions and prevent explosions require detailed investigations and accurate calculations instead of superficial and personal experience. In this context, possible leakages and leaks occurring around the LPG tank and its connections in a real enterprise were evaluated and the border of possible explosive atmosphere areas was calculated by the ALOAH program according to the TS 60079-10-1 standard. Based on the secondary discharge of the LPG from the bottom of the tank, the discharge characteristics were calculated as 4.946578 and 3.926692 m 3 /s at sonic and subsonic conditions respectively, and region radii, 10.8 m. The explosive atmosphere of the LPG tank was concluded that matched well the definition of Zone 2. The risk severity score of explosive atmospheres was calculated as 12 by using the risk assessment method of matrix system with approximations, possible in a week (3P), and the effect that could cause serious injury (4P). Serious threats and devastating effects were fictionalized clearly by explosion scenarios of the LPG tank. The calculations of explosive borders for flammable chemicals are necessary to prevent explosions, fires, and toxic effects of leaked chemicals by taking measurements on time. It is also necessary to calculate explosive areas and possible sceneries for each chemical separately for accurate results and effective control.

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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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Flammability limits, limiting oxygen concentration and minimum inert gas/combustible ratio of H2/CO/N2/air mixtures

Cited by 41 publications

References 7 publications

Lean Flammability Limits of Syngas/Air Mixtures at Elevated Temperatures and Pressures

Lean Flammability Limits of Syngas/Air Mixtures at Elevated Temperatures and Pressures

The Risk Calculation of Hazardous Zones Created By Flammable And Explosive Chemicals, LPG Tank Example

Micromechanism of the Initiation of a Multiple Flammable Gas Explosion

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