Influence of coal rank and pretreatment on residual ash particle size

Kramlich, John C.; Newton, G.H.

doi:10.1016/0378-3820(94)90012-4

Cited by 11 publications

(5 citation statements)

References 14 publications

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“…An examination of the mass fraction in the 1−5 μm size range indicated that for combustion of a 53−63 μm coal sample in a drop tube furance, 24% of the residual ash was in the 1−5 μm range, whereas for combustion of a 75−90 μm coal, only 16% was in this range. Kramlich investigated ash size distributions from size fractions of pulverized coals. Coals were nominally sized into <18 μm, 18−37 μm, 37−85 μm, and >85 μm size cuts by aerodynamic classification.…”

Section: Resultsmentioning

confidence: 99%

The Formation and Emission of Particulate Matter during the Combustion of Density Separated Coal Fractions

Liu

Yao

et al. 2008

Energy Fuels

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The present study is a further effort to extend our knowledge of the included and excluded mineral characteristics responsible for the formation of particulate matter (PM). A Chinese bituminous coal was first separated into three density fractions using the float-sink method: heavy (>2.0 g/cm 3 ), medium (1.4-2.0 g/cm 3 ) and light (<1.4 g/cm 3 ). Then, combustion and pyrolysis of coal with different density fractions were carried out in a laboratory-scale drop tube furnace to understand the formation mechanism of inhalable particulate matter, less than 10 µm (PM 10 ) and less than 1 µm (PM 1 ). PM 10 was collected with a 13-stage low pressure impactor (LPI) having aerodynamic cutoff diameters ranging from 10.0 to 0.03 µm for a size-segregated collection. The experimental results indicated that the light fraction of the coal produced 44 wt % of total PM 10 and 45 wt % of total PM 1 . The medium fraction of the coal contributed 52 wt % of total PM 10 and 49 wt % of total PM 1 . The heavy fraction contributed 4 wt % of total PM 10 and 6 wt % of total PM 1 . The light fraction and the medium fraction of the coal contained mostly included mineral and the heavy fraction contained largely excluded minerals. The PM 10 and PM 1 contents formed by the excluded minerals were very low compared to those formed primarily from included minerals. The proportion of the minerals in the light density fraction converted into PM 1 and PM 10 was the highest, with their weight percentages being 9.59% and 43.49%, respectively. There were three reasons for this. One of reasons was the mineral particle size. The median mineral size in the light density fraction coal was smallest. However, the median size of each coal fraction was almost the same. Another reason was mineral transformation during combustion. The light fraction and the medium fraction of the coal contained mostly included minerals, and the heavy fraction contained largely excluded minerals. The transformations of included and excluded minerals were largely different and played a different role during coal combustion. The last reason was char fragmentation. Char formed by the light coal fraction was easier to fragment and subsequently formed more fine ash particles. This was because the swelling ratio, BET surface area, and total pore volume of char decreased with increasing parent coal density.

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Section: Resultsmentioning

confidence: 99%

The Formation and Emission of Particulate Matter during the Combustion of Density Separated Coal Fractions

Liu

Yao

et al. 2008

Energy Fuels

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“…Some publications have discussed HTEs released from coal combustion with respect to the following aspects: the HTE size-distribution in fly ashes and their enrichment in the submicrometer particles; ,, the formation and transformation of fly ash particles; , the direct gaseous emissions of several volatile HTEs (i.e., Hg, Se and As); and the mobility and leaching behavior of HTEs in coal. ,,, The behavior of trace elements during coal combustion depends largely on their volatility, with the volatilization trends of trace elements relying on their modes of occurrence, the combustion conditions, combustor structure, as well as the rank of coals. − …”

Section: Behavior Of Htes During Coal Combustionmentioning

confidence: 99%

A Review of Key Hazardous Trace Elements in Chinese Coals: Abundance, Occurrence, Behavior during Coal Combustion and Their Environmental Impacts

et al. 2013

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“…It is therefore then suggested that the Zn is remaining in the flue gas and by-passing the water cooled sections and cyclone trap of the CTF. Researchers [37][38][39][40][41] mention trace elements that are subject to vaporisation within a PF furnace such as Zn maybe enriched within submicron particles (Fig 4). Enrichment occurs via a condensing mechanism whereby volatile species undergo heterogeneous condensation and heterogeneous nucleation.…”

Section: Mass Balancementioning

confidence: 99%

An experimental study of ash behaviour and the potential fate of ZnO/Zn in the Co-combustion of pulverised South African coal and waste tyre rubber

Singh

Nimmo

Williams

2013

Fuel

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A Novel combustion application utilising waste tyre rubber (WTR) as a secondary fuel in pulverised coal power plants is presented. Co-combustion of a South African coal (SAf) with WTR at the fuel fractions (FF) 4.1%, 14.1% and 19.7% along with the pure firing of WTR was conducted in an 80 kWth combustion test facility (CTF). This study assessed the potential slagging and fouling behaviour of the resultant ashes produced from co-firing SAf/WTR and pure fired WTR. XRF and ICP/OES analysis of the co-fired SAf/WTR and pure fired WTR ashes revealed a high composition of acidic oxides. Based on the fusibility indices (B/A, RS, SR, F and Fu) it was determined that co-fired SAf/WTR and pure fired WTR ashes carry a low risk of slagging and fouling. ZnO is incorporated in the manufacturing of tyres as a compounding additive. ZnO is present within raw WTR, posing the question as to its fate during combustion. In this study ash collected and analysed from the pure fired WTR and co-fired SAf/WTR exhibited lower levels of Zn than anticipated. It is suggested that ZnO remains in the vapour phase within the CTF at temperatures >1200 o C. Experimental analysis found Zn enrichment at lower temperatures was not significant within the fly ash collected by the cyclone trap or ash deposits collected from the water cooled sections of the CTF. This suggests that Zn could be forming a submicron aerosol. It is further noted that ZnO/Zn is not likely to contribute significantly in the slagging/fouling mechanisms, due to its volatile nature. However this present study highlights the need for further experimental assessment of co-firing SAf/WTR required prior to any industrial application.

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Influence of coal rank and pretreatment on residual ash particle size

Cited by 11 publications

References 14 publications

The Formation and Emission of Particulate Matter during the Combustion of Density Separated Coal Fractions

The Formation and Emission of Particulate Matter during the Combustion of Density Separated Coal Fractions

A Review of Key Hazardous Trace Elements in Chinese Coals: Abundance, Occurrence, Behavior during Coal Combustion and Their Environmental Impacts

An experimental study of ash behaviour and the potential fate of ZnO/Zn in the Co-combustion of pulverised South African coal and waste tyre rubber

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