Behaviour of elements and minerals during preparation and combustion of the Pernik coal, Bulgaria

Vassilev, Stanislav V.; Eskenazy, Greta M.; Vassileva, Christina G.

doi:10.1016/s0378-3820(01)00186-2

Cited by 116 publications

(68 citation statements)

References 50 publications

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“…CO : AC 0 (60 mol/g) AC 50 (70 mol/g) AC 100 (80 mol/g) AC 150 (140 mol/g) 2 Thus, the number of carbon active sites formed up to 500°C as well as the HCl decrease value (Table S2 in the Supporting Information) was larger with the sample activated for a longer time. It is of interest to examine the relationship between both amounts.…”

Section: Energy and Fuelsmentioning

confidence: 93%

Evolution of Hydrogen Chloride and Change in the Chlorine Functionality during Pyrolysis of Argonne Premium Coal Samples

et al. 2012

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In order to understand chlorine chemistry in coal pyrolysis, the dynamics of HCl evolution and changes in chlorine functional forms during temperature-programmed pyrolysis of eight Argonne premium coal samples have been examined with an online HCl-monitoring technique and by the Cl 2p X-ray photoelectron spectroscopy (XPS) method. The rate profiles of HCl evolved show at least three distinct peaks at 390, 520, and 600°C, and the presence of these peaks depends strongly on the type of coal. The HCl peak at 390°C appears with four coals alone and becomes considerably small by water washing, whereas the high-temperature peaks above 450°C observed with almost all of the coals do not change significantly after washing. Yields of HCl up to 1000°C are in the range of 50−90% in many cases, and the yield tends to decrease with increasing atomic Ca/Cl ratio in coal. The chlorine XPS analyses show that the chlorine in each coal is enriched at the surface and composed of inorganic and organic functional forms. The extent of the enrichment and proportion of organic chloride species increase after pyrolysis at 450°C, whereas they decrease at high temperatures of 800 and 1000°C. Some model experiments followed by the chlorine XPS measurements show that the reaction of HCl with carbon active sites proceeds readily at 500°C to produce organic C−Cl forms, which release HCl again above 500°C upon reheating in an inert gas. On the basis of the abovementioned results, it is possible that HCl evolved below 450°C in coal pyrolysis comes predominantly from water-soluble chlorine functional groups in coal, whereas HCl formation above 450°C originates mainly from organic chlorides, which could be present inherently in coal and/or may be formed by secondary reactions of HCl evolved at a lower temperature with carbon active sites in the nascent char.

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Section: Energy and Fuelsmentioning

confidence: 93%

Evolution of Hydrogen Chloride and Change in the Chlorine Functionality during Pyrolysis of Argonne Premium Coal Samples

et al. 2012

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“…The float-sink test provides not only a reference for determining the washability of a given coal, but also an effective tool for evaluation of the affinities of various trace elements [25]. The ash yields, the contents of sulfur, and various trace elements in the sludge, the ROM coal, and the seven density fractions were all determined and listed in Table 3.…”

Section: Organic Affinities Of Trace Elementsmentioning

confidence: 99%

Washability and Distribution Behaviors of Trace Elements of a High-Sulfur Coal, SW Guizhou, China

et al. 2018

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Abstract:The float-sink test is a commonly used technology for the study of coal washability, which determines optimal separation density for coal washing based on the desired sulfur and ash yield of the cleaned coal. In this study, the float-sink test is adopted for a high-sulfur Late Permian coal from Hongfa coalmine (No.26), southwestern Guizhou, China, to investigate its washability, and to analyze the organic affinities and distribution behaviors of some toxic and valuable trace elements. Results show that the coal is difficult to separate in terms of desulfurization. A cleaned coal could theoretically be obtained with a yield of 75.50%, sulfur 2.50%, and ash yield 11.33% when the separation density is 1.57 g/cm 3 . Trace elements' distribution behaviors during the gravity separation were evaluated by correlation analysis and calculation. It was found that Cs, Ga, Ta, Th, Rb, Sb, Nb, Hf, Ba, Pb, In, Cu, and Zr are of significant inorganic affinity; while Sn, Co, Re, U, Mo, V, Cr, Ni, and Be are of relatively strong organic affinity. LREE (Light rare earth elements), however, seem to have weaker organic affinity than HREE (Heavy rare earth elements), which can probably be attributed to lanthanide contraction. When the separation density is 1.60 g/cm 3 , a large proportion of Sn, Be, Cr, U, V, Mo, Ni, Cd, Pb, and Cu migrate to the cleaned coal, but most of Mn, Sb and Th stay in the gangue. Coal preparation provides alternativity for either toxic elements removal or valuable elements preconcentration in addition to desulfurization and deashing. The enrichment of trace elements in the cleaned coal depends on the predetermined separation density which will influence the yields and ash yields of the cleaned coal.

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“…The latter case is of minor importance in the Hüsamlar samples as calcite occurs in a few samples only (table 4). Lime mainly derives from calcite and aragonite breakdown (Vassilev and Vassileva 1996;Fernandez-Turiel et al 2004), and haematite from the oxidation of pyrite or other Fe-bearing inorganic constituents (Vassilev and Vassileva 1996;Vassilev et al 2001). …”

Section: Mineral Matter In Coalmentioning

confidence: 99%

Palaeoenvironmental reconstruction of Hüsamlar coal seam, SW Turkey

et al. 2015

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TheÖren and Yatagan Basins in SW Turkey host several Miocene coal deposits currently under exploitation for power generation. The present study aims to provide insight into the palaeoenvironmental conditions, which controlled the formation of the Hüsamlar coal seam located inÖren Basin. The coal seam displays many sharp alternations of matrix lignite beds and inorganic, lacustrine sediment layers. The coal is a medium-to-high ash lignite (10.47-31.16 wt%, on dry basis) with high total sulphur content (up to 10 wt%, on dry, ash-free basis), which makes it prone to self-combustion. The maceral composition indicates that the peat-forming vegetation consisted of both arboreal and herbaceous plants, with the latter being predominant in the upper part of the seam. Mica and feldspars contribute to the low part of the seam; carbonates are dominant in the upper part, whereas quartz and pyrite are present along the entire coal profile. The sudden transitions of the telmatic to the lacustrine regime and reverse is attributed to tectonic movements that controlled water table levels in the palaeomire, which affected surface runoff and hence, clastic deposition.

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Behaviour of elements and minerals during preparation and combustion of the Pernik coal, Bulgaria

Cited by 116 publications

References 50 publications

Evolution of Hydrogen Chloride and Change in the Chlorine Functionality during Pyrolysis of Argonne Premium Coal Samples

Evolution of Hydrogen Chloride and Change in the Chlorine Functionality during Pyrolysis of Argonne Premium Coal Samples

Washability and Distribution Behaviors of Trace Elements of a High-Sulfur Coal, SW Guizhou, China

Palaeoenvironmental reconstruction of Hüsamlar coal seam, SW Turkey

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