Influence of coal tar–water emulsion on carbonisation of caking coals

Tramer, A.; Zubkova, Valentina; Prezhdo, V. V.; Wrobelska, K.; Kosewska, M.

doi:10.1016/j.jaap.2006.12.019

Cited by 7 publications

(5 citation statements)

References 27 publications

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“…Our earlier works [15,16,20,21] and the works by other authors [19] proved that the additive in the amount of 2 wt.% is sufficient enough to determine the influence of the additive on the trends of changes in the mechanism of coal pyrolysis.…”

Section: Methodsmentioning

confidence: 88%

“…PAHs caused destabilization of dispersive interactions in the structure of coals. That is why the addition of little amount of CTP and coal tar (containing PAHs) influenced the structural transformations of the plastic layer of coals along with the pressure within this layer and changed the texture of the pore wall material of coke [15,16].…”

Section: Introductionmentioning

confidence: 99%

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The influence of addition of coal tar pitch (CTP) and expired pharmaceuticals (EP) on properties and composition of pyrolysis products for lower and higher rank coals

Zubkova

Czaplicka

Puchala

2016

Fuel

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Section: Methodsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

The influence of addition of coal tar pitch (CTP) and expired pharmaceuticals (EP) on properties and composition of pyrolysis products for lower and higher rank coals

Zubkova

Czaplicka

Puchala

2016

Fuel

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“…Tramer et al [18] used the same technique to study the effect of coal tar pitch (applied as an emulsion) on carbonisation behaviour and found that the effect of the pitch depended greatly on the coal or coal blend it was intermixed with. When applied to a poorly caking coal the pitch plasticised the coal leading to an increased swelling range and higher gas pressure, but also a greater pressure drop in the plastic layer and consequently greater compaction.…”

Section: Discussionmentioning

confidence: 99%

Influence of coal thermoplastic properties on coking pressure generation: Part 2 – A study of binary coal blends and specific additives

Duffy

Mahoney

Steel

2010

Fuel

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a b s t r a c tA number of coal blends and pitch/coal blends were evaluated using rheometry, thermogravimetric analysis and microscopy to confirm and further elucidate the coking pressure mechanism previously proposed by Duffy et al. (2007) [1]. We confirm that blending a low rank, high fluidity, low coking pressure coal, with a high rank, low fluidity, high coking pressure coal can significantly reduce the coking pressure associated with the latter. Interestingly, blending does not necessarily result in a fluidity that is midway between that of the two coals; sometimes the fluidity of the blend is less than that of the low fluidity coal, especially when the coals are significantly different in rank. This occurs because the increase in complex viscosity (g*) through resolidification of the low rank, high fluidity coal counteracts the reduction in g* resulting from softening of the high rank, low fluidity coal. It has also been confirmed that the g* of the resultant blend can be estimated from the g* of each component coal using a logarithmic additivity rule commonly employed for polymer blends.Polarised light microscopy has indicated that the degree of mixing between coals of different rank is minimal, with fusion restricted to the particle surface. It is therefore inappropriate to think of such a coal blend in the same way as a single coal, since each component coal behaves relatively independently. This limited fusion is important for understanding the coking pressure mechanism for blends. It is proposed here that the lower rank coal, which softens at lower temperature, is able to expand into the interparticle voids between the high rank coal that is yet to soften, and these voids can create channels for volatiles to traverse. Then, and importantly, when the high rank coal begins to expand, the pore structure developed in the resolidified structures of the low rank coal can facilitate removal of volatiles, while the resolidified material may also act as a suitable sorbent for volatile matter. This is considered to be the primary mechanism by which coal blending is able to alleviate coking pressure, and applies to addition of inert material also.Addition of a coal tar pitch was found to increase fluidity but also to extend the thermoplastic range to lower temperatures. This caused an increase in the swelling range, which was accompanied by a long plateau in g*, a feature which has previously been observed for certain high fluidity, high pressure coals. Elasticity and g* at the onset of expansion were also higher for both the pitch impregnated coals and the high pressure blends, which supports previous findings for singly charged high pressure coals, and confirms the potential use of such criteria for identifying potentially dangerous coals/ blends.

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“…The research conducted by Nomura and Arima [3] proved that the addition of a coalderived binder can reduce the yield of volatile products from the blend during pyrolysis at the temperature below 450 • C. Coal tar and coal tar pitch (CTP) have been known for a long time as additives that improve the fluidity of coals [4][5][6][7][8] and their caking properties [3,4]. The authors of the works [9,10] suggest that pitch additives can be used as additives that bring back the lost thermoplastic abilities to low-oxidized coals.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Coal Tar Pitches on Thermal Behaviour of a High-Volatile Bituminous Polish Coal

Zubkova

Strojwas

2022

Materials

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The influence of three coal tar pitches (CTPs), having softening points at 86, 94, and 103 °C, on the thermal behaviour of a defrosted high-volatile coal during co-carbonization and co-pyrolysis was studied. The following research techniques were used: X-raying of the coked charge, TG/FT-IR, ATR and UV spectroscopies, extraction, SEM, STEM, and XRD. It was determined that CTP additives change the structure of the coal plastic layer, the thickness of its zones, and the ordering degree of the structure of semi-cokes to a different extent and independently from their softening points. The softening points of CTPs do not influence the composition and yield of volatile products emitted from blends with pitch as well as the composition, structural-chemical parameters, and topological structure of material extracted from coal blends. It is suggested that such a lack of existence of any correlation between the softening points of CTPs and the degree of their influence on the thermal behaviour of coal was caused by the presence of the atoms of metals (Fe and Zn) in the CTPs. These atoms change the course of the carbonization of the CTPs themselves and their influence on organic substance of coal in blends with CTPs.

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Influence of coal tar–water emulsion on carbonisation of caking coals

Cited by 7 publications

References 27 publications

The influence of addition of coal tar pitch (CTP) and expired pharmaceuticals (EP) on properties and composition of pyrolysis products for lower and higher rank coals

The influence of addition of coal tar pitch (CTP) and expired pharmaceuticals (EP) on properties and composition of pyrolysis products for lower and higher rank coals

Influence of coal thermoplastic properties on coking pressure generation: Part 2 – A study of binary coal blends and specific additives

The Influence of Coal Tar Pitches on Thermal Behaviour of a High-Volatile Bituminous Polish Coal

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