Mechanism of gas flow through coal

Karn, F.S.; Friedel, R. A.; Sharkey, A.G.

doi:10.1016/0016-2361(75)90045-9

Cited by 19 publications

(22 citation statements)

References 5 publications

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“…In contrast to these ideas, Karn et al (1975) reported methane flows in coal as high as lo-' to 2 cmZ/s atm, the higher rates associated with the more porous coals having increased accessibility of internal surface area. Gan et al (1972) showed in their gas adsorption experiments that the adsorption was a diffusion-limited process: nitrogen surface areas measured at -195°C were orders of magnitude less than the C 0 2 surface areas measured at 25°C.…”

Section: Conclusion and Significancementioning

confidence: 71%

Reaction regimes in coal oxidation

Karsner

Perlmutter

1981

AIChE Journal

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A series of seven coals were oxidized in a fixed bed reactor to determine the controlling reaction regimes during mild coal oxidation. The effects of coal porosity and particle size, reactor temperature, and oxygen partial pressure were evaluated. The results show that coal‐oxygen reactions are controlled by the rate of internal gaseous diffusion for most coals, and by the rate of chemical reaction for the most porous coal of the set tested. Particle size effects also suggest internal diffusional control. Determinations of cumulative oxygen deposition indicate that surface areas several orders of magnitude greater than the superficial surface can participate in oxidation reactions, putting in doubt the applicability of the model previously derived by Kam et al. (1976a) for external mass transfer control.

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Section: Conclusion and Significancementioning

confidence: 71%

Reaction regimes in coal oxidation

Karsner

Perlmutter

1981

AIChE Journal

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“…Using a co 2 cw laser, Karn, et al, 1972, were able to heat coal samples at 140 W/cm 2 • The difference between these results and those \'Jith the pulsed laser were quite marked, and pulsed laser giving a higher yield of volatiles.…”

Section: Laser Heating Of Coalmentioning

confidence: 90%

Volatile production during preignition heating. Final technical report, 15 September 1980-30 September 1982

Ballantyne¹,

Chou²,

Flusberg³

et al. 1983

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“…Some scholars believe that gas emission of coal particles is a diffusion process, and established mathematical models based on Fick's law [11][12][13]. Gas diffusion through coal include molecular diffusion in small pores and bulk diffusion in larger pores [14]. Thus, the physical characteristics of pore are very important for the establishment of mathematical and physical model of coal gas emission [15,16].…”

Section: Introductionmentioning

confidence: 99%

Gas emission characteristics of tectonic coal in the initial stage: Application for coal and gas outburst prediction

Zhang

Huo

Shu

et al. 2022

Preprint

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Coal and gas outburst is one of the most disasters threating the safety and production of coal mines. Accurate description of the gas emission characteristics in the initial stage for tectonic coal is the key to improving the prediction accuracy of coal and gas outburst. In this work, the gas emission test of original and tectonic coal particles under the constant temperature was carried out. The optimal mathematical model suitable for the gas emission in the initial stage was then analyzed. Moreover, the time influencing factors of the optimal mathematical model were discussed. The research results show that cumulative gas desorption amount during 0-7 minute for tectonic coal is 1.28-1.41 times as much as that for original coal. The applicability of current mathematical model for describing the gas emission characteristics of tectonic coal in the initial stage has limitations. Five typical mathematical expressions are selected and compared to fit gas emission curve in the initial stage. Considering the sensitivity of parameters in outburst prediction, the optimal mathematical model was obtained. In addition, the time factor has a great influence on the application effect of mathematical model in coal and gas outburst prediction. For current mathematical model, the errors of tectonic coal are all negative. The greater the gas pressure and the later the measurement time, the greater the error. The errors in 1~6 min are -0.46%~-1.78%, and the errors in 2~7 min are -1.00%~-3.86%, which is not conducive to the safety of outburst prediction. Therefore, the optimal mathematical model has the possibility to overcome the limitations of current mathematical model. The research results provide a theoretical basis for the correction of coal and gas outburst prediction indicators.

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Mechanism of gas flow through coal

Cited by 19 publications

References 5 publications

Reaction regimes in coal oxidation

Reaction regimes in coal oxidation

Volatile production during preignition heating. Final technical report, 15 September 1980-30 September 1982

Gas emission characteristics of tectonic coal in the initial stage: Application for coal and gas outburst prediction

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