Pollutant emission characteristics and interaction during low-temperature oxidation of blended coal

Chen, Gang; Ma, Xiaoqian; Lin, Musong; Peng, Xiaowei; Yu, Zhaosheng

doi:10.1016/j.joei.2014.12.001

Cited by 18 publications

(6 citation statements)

References 24 publications

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“…Self-heating of coal in stockpiles has long been regarded as a safety concern and additionally, pre-oxidation of coal would incur considerable loss of coal calorific value and seriously affect caking property [12][13][14]. More recently the liberation of large amounts of greenhouse-relevant gases and hazardous substances, such as arsenic, mercury, and lead from coal stockpile combustion or oxidation has raised considerable concerns from global communities [15][16][17][18]. Despite the long history of the problem, it has also been accepted that the physical and chemical processes responsible for this problem is extremely complex [12].…”

Section: Introductionmentioning

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: Introductionmentioning

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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“…Waste consist of different character calorific value and different-sized particles, the average calorific value of which is dependent on external parameters: temperature, pressure, humidity. Average heat of combustion of MSW ~8000 kJ/kg [12][13][14][15][16]. The combustion of MSW consumes a large amount of oxygen O2, which increases considerably with increasing content of the waste plastic materials.…”

Section: Methods Of Utilization Of Mswmentioning

confidence: 99%

“…Already in the nearest future waste incineration, installations with development of additional amount of thermal and electric energy will successfully compete with the traditional systems of classical power [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

High-temperature processing of municipal solid waste

2019

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At present, processing and recycling of municipal solid waste (MSW) has become more relevant in our country and the world at large. This problem concerns large towns and cities, where every year millions of tons of all kinds of fractions of household waste are produced. Disposal or recycling of solid waste is an environmental issue, but it is associated with the solution of complex technical, energy and economic challenges. The purpose of this study is to identify the advantages and disadvantages of modern methods of processing and disposal of MSW with the prospect of developing and creating a device for recycling MSW taking into account modern approaches to energy saving and environmental protection. The main results of the study are to create a simple, reliable and technically sound method of MSW disposal to obtain additional energy. The significance of the results obtained for the construction industry is the design of a device for the disposal of solid waste with the production of solid combustion products and further their use as building materials and products for various purposes. Because of the technological process of MSW processing, it becomes possible to generate some returns through use of resulting thermal energy for electricity production.

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“…1,2 It is neither easy nor efficient to directly fire the raw coal for energy. 1,3,4 On the other hand, low-rank coal is generally rich in gellified microcomponent and side chain of organic structure. As such, low-rank coal can be used as raw materials for chemical industry.…”

Section: Introductionmentioning

confidence: 99%

“…Numerous studies have been reported about co-combustion of solid fuels, 3,9–11 , whereas research on semi-coke only occupies a tiny fraction. Besides, all these works were conducted on thermogravimetric analyzer 7 or lab-scale test bed, 5,6 to investigate the thermal behavior of the blended fuel.…”

Section: Introductionmentioning

confidence: 99%

Computational fluid dynamics investigation on the effect of co-firing semi-coke and bituminous coal in a 300 MW tangentially fired boiler

Wang

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part A:

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In this paper, the effect of co-firing semi-coke in a 300 MW tangentially fired boiler was numerically investigated. The results indicate that the incomplete combustion heat loss and NO x emission both increase with semi-coke co-fired ratio. Semi-coke may be injected into the furnace at a different height, which can lead to different thermal efficiency and NO x emission. It is suggested that semi-coke should not be fed from the top or bottom layer burners, since this could give rise to high carbon content respectively in fly ash and bottom slag. In addition, injecting semi-coke from the top burners could significantly increase the NO x emission. Under 1/2 co-firing ratio, the optimal fuel allocation is that feeding semi-coke from the B, D, and E layer burners. The growth in semi-coke particle size could increase the unburned carbon loss and NO x emission. It is highly recommended to reduce the unburned carbon loss under semi-coke co-fired condition by increasing the stoichiometric ratio of primary air for semi-coke. As it is increased from 0.25 to 0.3, the combustion efficiency of the co-fired condition is 99.47%, the same as when only firing bituminous coal, and the NO x emission is about 30% higher.

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Pollutant emission characteristics and interaction during low-temperature oxidation of blended coal

Cited by 18 publications

References 24 publications

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

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

High-temperature processing of municipal solid waste

Computational fluid dynamics investigation on the effect of co-firing semi-coke and bituminous coal in a 300 MW tangentially fired boiler

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