Model predictions on self-heating and prevention of stockpiled coals

Krajčiová, M; Jelemenský, Ľudovít; Kiša, Michal; Markoš, Jozef

doi:10.1016/j.jlp.2004.02.002

Cited by 34 publications

(6 citation statements)

References 8 publications

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“…Heat convection occurs between coal to gas and the efficiency of heat convection is mainly determined by velocity of gas advection within inter-particle channels. Whilst heat radiation could be a major contributor in the surface of stockpile because of solar energy it absorbed but in deep stockpile heat radiation can be negligible [48].…”

Section: Brief Mechanism Of Spontaneous Heating Of Coal Stockpilementioning

confidence: 99%

Transient CFD modelling of low-temperature spontaneous heating behaviour in multiple coal stockpiles with wind forced convection

Zhang

Liang

Ren

et al. 2016

Fuel Processing Technology

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G. (2016). Transient CFD modelling of low-temperature spontaneous heating behaviour in multiple coal stockpiles with wind forced convection. Fuel Processing Technology, 149 55-74.Transient CFD modelling of low-temperature spontaneous heating behaviour in multiple coal stockpiles with wind forced convection AbstractSpontaneous heating of coal stockpile has long been a thermal dynamic hazard during coal storage, processing, and transport. A transient non-equilibrium thermal CFD model has been developed to study the low-temperature self-heating behaviour of coal in multiple stockpiles under different prevailing wind conditions. Modelling results from the initial steady wind flow simulation indicate that a wake region can be induced on the leeward side of each coal stockpile. Pressure coefficient drops when the wind stream encounters or leaves a stockpile and the pressure coefficient profiles of multiple stockpiles tend to have more resemblance with a wider spacing. The first stockpile acts like a wind barrier to the adjacent stockpiles and the maximum temperature of it tends to be the first approaching the critical temperature. A 'hot spot' will develop and then migrate towards deep regions in each of these stockpiles that are loosely compacted under higher wind velocity conditions. Wind velocity and porosity of stockpile have significant influences on self-heating behaviour of the stockpiles and transport pattern of gaseous products liberated by coal oxidation. Compacting stockpiles from loosely packed scenario to slightly packed scenario might not be able to slow down the temperature rising rate at low-temperature range but could considerably minimize the volume of deteriorated coal. The highest temperature rising profiles of the stockpiles located in downwind side can approach to that of the first stockpile, particularly when they are more widely stacked. Stacking coal stockpiles as close as practically possible is recommended to maximise the "protection" of adjacent stockpiles but would cause undesirable accumulation of carbonic gases. Stockpiles in low height and gentle slope will have a prolonged safe storage period, especially for the first stockpile directly facing the wind direction. However, it may not slow down the self-oxidation process of the adjacent stockpile at very initial stage due to "weakened protection" of the first stockpile. This study has practical reference to coal industry especially where multiple coal stockpiles require to be constructed. 13The first stockpile acts like a wind barrier to the adjacent stockpiles and the maximum temperature of it tends to 14 be the first approaching the critical temperature. A 'hot spot' will develop and then migrate towards deep 15 regions in each of these stockpiles that are loosely compacted under higher wind velocity conditions. Wind 23Stockpiles in low height and gentle slope will have a prolonged safe storage period, especially for the first 24 stockpile directly facing the wind direction. However, it may not slow down the self-oxidation process o...

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Section: Brief Mechanism Of Spontaneous Heating Of Coal Stockpilementioning

confidence: 99%

Transient CFD modelling of low-temperature spontaneous heating behaviour in multiple coal stockpiles with wind forced convection

Zhang

Liang

Ren

et al. 2016

Fuel Processing Technology

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“…An industrial compost pile size can vary between 6 m and 30 m in both height and width, and a few hundred metres in length [7,17]. Following the work of Krajčiová et al [11], the angle at the base of the slab is set to 60 degrees, as in the coal model.…”

Section: Governing Equationsmentioning

confidence: 99%

A two dimensional, reaction-diffusion model of compost piles

Luangwilai

Sidhu

Nelson

2012

ANZIAMJ

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We consider the self heating process in a two dimensional spatially dependent model of a compost pile which incorporates terms that account for self heating due to both biological and oxidation mechanisms. As moisture is a crucial factor in both the degradation process and spontaneous ignition within a compost pile, this model consists of four mass-balance equations, namely, energy, oxygen, vapour and liquid water concentrations. Analyses are undertaken for different initial water contents within the compost pile. We show that when the water content is too low, the reaction is almost negligible; whereas when it is too high, the reaction commences only when the water content evaporates and the water ratio drops to within an appropriate range. However, for an intermediate water content range, the biological reaction is at its optimum and there is a possibility of spontaneous ignition within the compost pile.

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“…And, unsteady analyses are employed to predict ignition delay. But, moisture content and volatiles in coal and solar radiation are not considered in this work, which have minor effects on coal ignition (Kraj ciov a et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

“…Additionally, several works employed air flow surrounding the piles (Akgun and Essenhigh, 2001;Kim and Sohn, 2012;Salinger et al, 1994). The effect of solar radiation on coal ignition was studied (Kraj ciov a et al, 2004).…”

Section: Introductionmentioning

confidence: 99%