Study of low-temperature oxidation of buckskin subbituminous coal and derived chars produced in ENCOAL process

Shamsi, Abolghasem; Shadle, Lawrence J.; Seshadri, K. S.

doi:10.1016/j.fuproc.2004.03.007

Cited by 26 publications

(11 citation statements)

References 20 publications

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“…As a high-efficiency clean technology for converting coal volatiles into oil, pyrolysis has attracted much attention from researchers with various research backgrounds. 1−4 Up to now, many coal pyrolysis technologies have been developed over the past century, mainly including the directheating pyrolysis technology, such as Toscoal technology, 5 DG technology, 6,7 LFC technology, 8,9 COED technology, 10,11 and Encoal technology, 12 and indirect-heating pyrolysis technology, such as W-D technology, Koppers technology, 13 and MRF technology. 14,15 The heat carrier in the former can be a solid heat carrier, such as char or hot ash, or a gaseous heat carrier, such as pyrolysis gas or flue gas.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Moisture Content in Coal on the Pyrolysis Behavior in an Indirectly Heated Fixed-Bed Reactor with Internals

Wang

et al. 2017

Energy Fuels

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The fixed-bed reactor with internals has been proposed to enhance the pyrolysis performance for coal. In this study, the pyrolysis behavior of different coal moisture contents and the reaction mechanism were investigated in an indirectly heated fixed-bed reactor with internals. The results showed that, at a furnace temperature of 900 °C, the increased coal moisture content went from 0.41 to 11.68 wt % and significantly modified the temperature fields, thereby prolonging the pyrolysis time to reach 500 °C and then enhancing the condensation and trapping of the coal at the bed center. Therefore, the tar yield and light tar content were raised from 9.21 and 63.7 wt % to 10.74 and 64.5 wt %, respectively. However, when the coal moisture content exceeded 16.77 wt %, the tar yield and light tar content decreased to 8.55 and 62.0 wt %, respectively. In addition, the higher heating value (HHV) of char with internals was dramatically higher than that without internals, and the char HHV in the reactor with internals rose primarily and then decreased with the increase in the coal moisture; meanwhile, its fixed carbon content of char showed an increase, followed by a decline. In contrast, the pyrolysis products varied slightly in the reactor without internals.

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Section: Introductionmentioning

confidence: 99%

Effect of the Moisture Content in Coal on the Pyrolysis Behavior in an Indirectly Heated Fixed-Bed Reactor with Internals

Wang

et al. 2017

Energy Fuels

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“…High volume of coal requires temporarily stored as one or multiple stockpiles in a storage yard of a coal mine site or a port before they can be transported to other destinations. Coal, as a carbonaceous material, is able to be oxidised and to liberate heat at ambient temperature with the presence of oxygen rich air [1][2][3][4]. Self-heating of coal stockpile will occur if the heat generated by coal oxidation is not adequately dissipated.…”

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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“…Oxygen consumption and index gases analysis of coal is a useful way to evaluate the oxidation activity of coal during low-temperature oxidation [1,25,26]. As shown in Figure 6, the oxygen consumption of raw coal was more than that of ILs-treated coals, where the oxygen consumption of BB coal and BO coal were less than that of BA coal.…”

Section: Oxygen Consumption and Index Gases Analysis During Low-tempementioning

confidence: 99%

Effect of Ionic Liquids on Low-Temperature Oxidation of Coal

Zhang

Jiang

et al. 2013

International Journal of Coal Preparation and Utilization

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Three 1-butyl-3-methyl imidazolium ([BMIm] þ ) based ionic liquids (ILs) with different anions, including tetrafluoroborate ([BF 4 ] À ), acetate ([Ac] À ), and trifluoromethane sulfonate ([OTf] À ), were selected to investigate the inhibition effect of ILs on low-temperature oxidation of coal by oxidizing raw coal and ILs-treated coals under air during 20-180 C. The coal structure was characterized by Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). The Raman results show that the ILs treatment can inhibit the low-temperature oxidation activity of disorder structure in coal. The FTIR results demonstrate that the ILs can break and dissolve the associated hydrogen bonds and methylene groups, so that the lowtemperature oxidation activity of ILs-treated coal is inhibited. The analysis on oxygen consumption and index gases of coals by gas chromatograph further confirms the spectra results that ILs treatment can inhibit the low-temperature oxidation of coal. The inhibition effect is in the order of [BMIm][OTf] > [BMIm][BF 4 ] > [BMIm][Ac].

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Study of low-temperature oxidation of buckskin subbituminous coal and derived chars produced in ENCOAL process

Cited by 26 publications

References 20 publications

Effect of the Moisture Content in Coal on the Pyrolysis Behavior in an Indirectly Heated Fixed-Bed Reactor with Internals

Effect of the Moisture Content in Coal on the Pyrolysis Behavior in an Indirectly Heated Fixed-Bed Reactor with Internals

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

Effect of Ionic Liquids on Low-Temperature Oxidation of Coal

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