Characterisation of HyperCoals from coals of various ranks

Takanohashi, Toshimasa; Shishido, Takahiro; Kawashima, Hiroyuki; Saito, Ikuo

doi:10.1016/j.fuel.2007.02.017

Cited by 82 publications

(52 citation statements)

References 13 publications

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“…Prior to deconvolution, the 13 C-NMR spectrum was adjusted using the Nuts Software. Then, the PFM module of the Origin Software was used to subtract the baseline, add peaks manually according to the spectrum shape and assignment of NMR structure The chemical shifts and assignment for the 13 C-NMR spectra of coal and its precursor have been summarized in previous studies [57][58][59][60][79][80][81][82][83][84][85], and the reported chemical shifts are mostly identical with only minor differences. The 13 C-NMR structure parameters and assignment used in the present study are given in Table 2 [84,[86][87][88].…”

Section: Samples and Analytical Methodsmentioning

confidence: 99%

13C-NMR Study on Structure Evolution Characteristics of High-Organic-Sulfur Coals from Typical Chinese Areas

Wei

Tang

2018

Minerals

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Abstract:The structure evolution characteristics of high-organic-sulfur (HOS) coals with a wide range of ranks from typical Chinese areas were investigated using 13 C-CP/MAS NMR. The results indicate that the structure parameters that are relevant to coal rank include CH 3 carbon (f al *), quaternary carbon, CH/CH 2 carbon + quaternary carbon (f al H ), aliphatic carbon (f al C ), protonated aromatic carbon (f a H ), protonated aromatic carbon + aromatic bridgehead carbon (f a H+B ), aromaticity (f a CP ), and aromatic carbon (f ar C ). The coal structure changed dramatically in the first two coalification jumps, especially the first one. A large number of aromatic structures condensed, and aliphatic structures rapidly developed at the initial stage of bituminous coal accompanied by remarkable decarboxylation. Compared to ordinary coals, the structure evolution characteristics of HOS coals manifest in three ways: First, the aromatic CH 3 carbon, alkylated aromatic carbon (f a S ), aromatic bridgehead carbon (f a B ), and phenolic ether (f a P ) are barely relevant to rank, and abundant organic sulfur has an impact on the normal evolution process of coal. Second, the average aromatic cluster sizes of some super-high-organic-sulfur (SHOS) coals are not large, and the extensive development of cross bonds and/or bridged bonds form closer connections among the aromatic fringes. Moreover, sulfur-containing functional groups are probably significant components in these linkages. Third, a considerable portion of "oxygen-containing functional groups" in SHOS coals determined by 13 C-NMR are actually sulfur-containing groups, which results in the anomaly that the oxygen-containing structures increase with coal rank.

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Section: Samples and Analytical Methodsmentioning

confidence: 99%

13C-NMR Study on Structure Evolution Characteristics of High-Organic-Sulfur Coals from Typical Chinese Areas

Wei

Tang

2018

Minerals

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“…It was determined that hard coals at the middle stage of metamorphism are most suitable for coal thermal dissolution processes that aim to produce coal-tar pitchlike products (Rahman et al, 2013;Takanohashi et al, 2008a;Sharma et al, 2008a). Japanese companies Kobe Steel Co. Ltd. and Mitsubishi Chemical Co. designed a process of obtaining ashless Hypercoal through a process of coal thermal dissolution and ash content of such Hypercoal is less than 0.01 wt.% Takanohashi et al, 2008a;Li et al, 2004;Okuyama et al, 2005). The process takes place at temperatures of 360-380°C, using a mixture of bicyclic aromatic hydrocarbons as solvent.…”

Section: Introductionmentioning

confidence: 99%

Getting an Alternative Pitch Binder by Thermal Dissolution of Coal

Kuznetsov¹,

Marakushina²,

Kazbanova³

et al. 2016

American Journal of Applied Sciences

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The process of thermal dissolution of medium metamorphosed coals in anthracene oil to produce an alternative pitch binder was studied. The process was carried out at temperatures from 350 to 400°C and pressure not higher than 2.5 MPa, without the use of hydrogen and catalysts. It was determined that during thermal dissolution hard coal of gaseous-fat grade demonstrated a higher activity compared with less metamorphosed gaseous coal. Under optimal conditions at a temperature of 350-380°C yields of pitch tar containing product are 63-75%. With regard to their composition and the main technical characteristics the isolated pitches are at the level in the middle between the coal-tar and oil pitches. Based on the yield data analysis, technical and environmental characteristics of the isolated pitch products a conclusion was made on the prospects of thermal dissolution process as an alternative method for preparing extractive pitch-a substitute for coal-tar pitch produced by coking process.

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“…When coke is made from low-quality coal, non-adhesion grain boundaries may result in large defects in coke. Shishido et al (6)(7)(8) reported that the strength of coke made from a large quantity of low-quality coal is increased by the addition of the binder, which is extracted from the coal, and has a high caking property. Arima (9) also reported that the drum index is increased by refining the grain of caking coal.…”

mentioning

confidence: 99%

Quantification of the Existence Ratio of Non-Adhesion Grain Boundaries and Factors Governing the Strength of Coke Containing Low-Quality Coal

Kanai

Yamazaki

Zhang

et al. 2012

JTST

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Abstract"Non-adhesion grain boundaries" are formed when low-quality coal grains do not adhere to other grains in the carbonization process because of the low dilation of coke. To better understand the effects of non-adhesion grain boundaries on coke strength, the relationship between the existence ratio of non-adhesion grain boundaries and coke strength was investigated quantitatively. The existence ratio of non-adhesion grain boundaries were measured quantitatively by observing the fracture cross-section of coke using scanning electron microscopy (SEM). Coke strength was measured with a diametral-compression test and an I-shape drum index test. As a result, non-adhesion grain boundaries increased with an increase in the blending ratio of low-quality coal. In particular, non-adhesion grain boundaries increased rapidly when the blending ratio of low-quality coal was over 50%. When the ratio was less than 50%, low-quality coals adhered to other caking coal. However, not many low-quality coals adhered to other caking coals when the ratio was over 50%. The tensile strength of coke was not affected by the porosity of coke. However, the tensile strength and the drum index were affected by the existence ratio of non-adhesion grain boundaries. Tensile strength decreased rapidly even for a few non-adhesion grain boundaries because significant defects caused a fracture in the diametral-compression test. However, the I-shape drum index decreased linearly with the existence ratio of the non-adhesion grain boundaries because many fractures occurred during 600 rotations in the drum. The strength of coke containing low-quality coal is governed by the existence ratio of non-adhesion grain boundaries rather than mean values such as the porosity of coke.

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Characterisation of HyperCoals from coals of various ranks

Cited by 82 publications

References 13 publications

13C-NMR Study on Structure Evolution Characteristics of High-Organic-Sulfur Coals from Typical Chinese Areas

13C-NMR Study on Structure Evolution Characteristics of High-Organic-Sulfur Coals from Typical Chinese Areas

Getting an Alternative Pitch Binder by Thermal Dissolution of Coal

Quantification of the Existence Ratio of Non-Adhesion Grain Boundaries and Factors Governing the Strength of Coke Containing Low-Quality Coal

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