The flame deflagration of hybrid methane coal dusts in a large-scale detonation tube (LSDT)

Ajrash, Mohammed Jabbar; Zanganeh, Jafar; Moghtaderi, Behdad

doi:10.1016/j.fuel.2017.01.038

Cited by 56 publications

(14 citation statements)

References 44 publications

(35 reference statements)

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“…18,19,21 In addition to the explosion characteristics, the ignitability, ame deagration and propagation properties of methane-air-coal dust mixture were explored. [22][23][24][25][26][27][28] However, little attention has been paid to the effect of coal dust volatility on explosion characteristics of methane-air-coal dust mixtures.…”

Section: Introductionmentioning

confidence: 99%

Experimental data revealing explosion characteristics of methane, air, and coal mixtures

Deng

Wang

et al. 2019

RSC Adv.

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Section: Introductionmentioning

confidence: 99%

Experimental data revealing explosion characteristics of methane, air, and coal mixtures

Deng

Wang

et al. 2019

RSC Adv.

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“…The maximum values of the static, dynamic and stagnation pressures were at 9.5% methane concentration. This adds to evidence that 9.5% represents the stoichiometric value of methane in air explosions (Ajrash et al, (2017) This may be attributed to the fact that at the 3 m and 6 m RS lengths, the flame didn't reach the end of the tube. However, as the length of methane injection increased to 12 m and 25 m, the flame reached to the last section of the DT (30 m) and significantly increased the static pressure.…”

Section: Maximum Pressure Risementioning

confidence: 77%

Deflagration of premixed methane–air in a large scale detonation tube

Ajrash

Zanganeh

Moghtaderi

2017

Process Safety and Environmental Protection

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Methane explosion hazards in pipes are of pivotal concern in chemical plants. Accurate knowledge of flame deflagration and its behaviours are required to reduce the consequences of accidental fires and explosions. Considering a lack of experimental work exists in large scale methane-air deflagration systems, a detonation tube (30 m long) was facilitated at the University of Newcastle to cover the knowledge gap in terms of boosting flame deflagration of low methane concentrations and also examining flame deflagration characteristics with different reactive lengths (3, 6, 12 and 25 m). The feature of injecting methane at varied reactive sections (RS) was achieved using a balloon isolation system, a 50 mJ chemical ignitor used to ignite the initial explosion section. The results revealed that stagnation pressure gradually increased, from 2.03 bar to 3.77 bar then 4.57 bar, with increasing RS length from 3 m to 6 m then 12 m, respectively. There was no significant influence of 1.25% or 2.5% methane concentrations on dynamic or stagnation pressures, however, they extended the travelling flame distance by about 3 m for RS lengths of 12 m and 25 m. At 9.5% methane concentration and for a RS of 12 m a state of fast deflagration was observed, associated with 5 bar pressure rise. The pressure wave up to 6.5 m was only a few milliseconds (about 15 ms) ahead of the flame for almost the full methane concentration range, however, after this point the gap between the pressure wave and the flame significantly varied in accordance to the methane concentration, where the data analysis at 15 m indicated that for 9% methane concentration the flame was only 21 ms behind the pressure wave, and for 5% and 15% methane concentration the flame was behind the pressure wave in the range of 55-93 ms. Due to the limited length of the DT compared with the large volume of methane injected, there was no significant influence on the flame deflagration properties when extending the RS length from 12 m to 25 m, as the mixture initially located after 12 m pushed out through the open end.

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“…The researchers measured the maximum explosion overpressure, the propagation velocity of the pressure wave along the tube and the minimum concentration of coal dust required for an explosion. Various researchers have studied the flammabilities of methane-coal dust mixtures (Amyotte et al 1991(Amyotte et al , 1993Cashdollar 1996;Rockwell and Rangwala 2013;Ajrash et al 2016Ajrash et al , 2017. The lower ignition limit of the mixture decreases as the ignition energy increases.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of the explosion pressure characteristics of micro- and nano-sized coal dust and methane–coal dust mixtures in a pipe

Tan

Liu

et al. 2020

Int J Coal Sci Technol

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Coal dust explosion accidents often cause substantial property damage and casualties and frequently involve nano-sized coal dust. In order to study the impact of nano-sized coal on coal dust and methane-coal dust explosions, a pipe test apparatus was used to analyze the explosion pressure characteristics of five types of micro-nano particle dusts (800 nm, 1200 nm, 45 lm, 60 lm, and 75 lm) at five concentrations (100 g/m 3 , 250 g/m 3 , 500 g/m 3 , 750 g/m 3 , and 1000 g/m 3 ). The explosion pressure characteristics were closely related to the coal dust particle size and concentration. The maximum explosion pressure, maximum rate of pressure rise, and deflagration index for nano-sized coal dust were larger than for its micro-sized counterpart, indicating that a nano-sized coal dust explosion is more dangerous. The highest deflagration index K st for coal dust was 13.97 MPa/(mÁs), indicating weak explosibility. When 7% methane was added to the air, the maximum deflagration index K st for methane-coal dust was 42.62 MPa/(mÁs), indicating very strong explosibility. This indicates that adding methane to the coal dust mixture substantially increased the hazard grade.

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The flame deflagration of hybrid methane coal dusts in a large-scale detonation tube (LSDT)

Abstract: Ajrash, Mohammed J.; Zanganeh, Jafar; Moghtaderi, Behdad. 'The flame deflagration of hybrid methane coal dusts in a large-scale detonation tube (LSDT)'.

Cited by 56 publications

References 44 publications

Experimental data revealing explosion characteristics of methane, air, and coal mixtures

Experimental data revealing explosion characteristics of methane, air, and coal mixtures

Deflagration of premixed methane–air in a large scale detonation tube

Comparative study of the explosion pressure characteristics of micro- and nano-sized coal dust and methane–coal dust mixtures in a pipe

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