Coal weathering and laboratory (artificial) coal oxidation

J, Kuś; Misz‐Kennan, Magdalena; Iccp,

doi:10.1016/j.coal.2016.11.016

Cited by 47 publications

(17 citation statements)

References 148 publications

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“…3.1. During June and subsequent monsoon months, volatile matter consistently increases possibly because of natural decomposition of fixed carbon and producing thereof volatile matter by oxidation process, weather (alternatively intense heat and intense rain) being conducive to that (Leonard 1977;Kus and Kennan 2017;Fredricks et al 1983). As a result seasonal variation of volatile matter content in coal (Fig.…”

Section: Effect Of Weathering On Proximate Analysis Of Coalmentioning

confidence: 98%

“…Initial increase in volatile content results due to adsorption of oxygen from the atmosphere. Subsequent erratic, but gradual decrease till 1st June 2016 to the level of 22% is possibly due to oxidation at low temperature with release of combustion products (Banerjee et al 2000;Leonard 1977;Kus and Kennan 2017;Jose et al 1996) and natural decomposition of various hydrocarbons as described in Sect. 3.1.…”

Section: Effect Of Weathering On Proximate Analysis Of Coalmentioning

confidence: 99%

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Effect of weathering on physico-chemical properties and combustion behavior of an Indian thermal coal

Aich

Nandi

Bhattacharya

2018

Int J Coal Sci Technol

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An open air stockpile of conical shape was formed with 3.5 m base diameter and 5 m height using 500 tons of-200 mm size ROM thermal coal on a concrete floor. Coal sample from the stockpile were collected at 30 days interval for analysis of various chemical properties like; proximate analysis, ultimate analysis, gross calorific value (GCV) and various combustion related properties such as ignition temperature, peak temperature, burnout temperature, maximum combustion rate, ignition index, burnout index, combustion performance index and combustion rate intensity index. Experimental results show that, due to weathering of coal fixed carbon decreased from 35.6% to 19.9%, elemental carbon (C) decreased from 46.6% to 28.6%, hydrogen (H) decreased from 3.3% to 2.9% and GCV decreased by up to 55% of original value during 330 days of storage of coal in an open atmosphere. Ash content of coal increased form 29.2% to 46.6% due to loss of combustibles. Sulfur (S) of coal was found to get increased from 0.33% to 1.08% during storage. The activation energy of coal combustion increased from 22 kJ/mol to 54 kJ/mol. Variation in combustion parameters signifies that weathering has significant negative impact on coal combustion properties as coal become difficult to ignite.

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Section: Effect Of Weathering On Proximate Analysis Of Coalmentioning

confidence: 98%

Section: Effect Of Weathering On Proximate Analysis Of Coalmentioning

confidence: 99%

Effect of weathering on physico-chemical properties and combustion behavior of an Indian thermal coal

Aich

Nandi

Bhattacharya

2018

Int J Coal Sci Technol

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“…The experimental data revealed good adsorption capacities of some heavy metal ions, such as Ni, Cu, Cd, and Pb. Kus et al [7] studied the characteristics of oxidized coal, and found that coal oxidation lead to chemisorption of oxygen at the coal surface along with the formation of acid functional groups such as hydroxyl, carbonyl, carboxyl, and others, which led to subsequent thermal decomposition and a decrease in the aliphatic and alicyclic carbons. And during advanced stages of coal oxidation, vitrinite in coal will develop very extensive microcracks and microfissures accompanied by oxidation rims.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nitric Acid Modification on Characteristics and Adsorption Properties of Lignite

et al. 2019

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The objective of this research was to explore the changes of the pore structure and surface properties of nitric-modified lignite and base the adsorption performance on physical and chemical adsorbent characteristics. To systematically evaluate pore structure and surface chemistry effects, several lignite samples were treated with different concentrations of nitric acid in order to get different pore structure and surface chemistry adsorbent levels. A common heavy metal ion contaminant in water, Pb2+, served as an adsorbate probe to demonstrate the change of modified lignite adsorption properties. The pore structure and surface properties of lignite samples before and after modification were characterized by static nitrogen adsorption, X-ray diffraction, Scanning electron microscope, Fourier transform infrared spectroscopy, zeta potential, and X-ray photoelectron spectroscopy. The experimental results showed that nitric acid modification can increase the ability of lignite to adsorb Pb2+. The adsorption amount of Pb2+ increased from 14.45 mg·g−1 to 30.68 mg·g−1. Nitric acid reacted with inorganic mineral impurities such as iron dolomite in lignite and organic components in coal, which caused an increase in pore size and a decrease in specific surface areas. A hydrophilic adsorbent surface more effectively removed Pb2+ from aqueous solution. Nitric acid treatment increased the content of polar oxygen-containing functional groups such as hydroxyl, carbonyl, and carboxyl groups on the surface of lignite. Treatment introduced nitro groups, which enhanced the negative electrical properties, the polarity of the lignite surface, and its metal ion adsorption performance, a result that can be explained by enhanced water adsorption on hydrophilic surfaces.

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“…Meanwhile, the evaporation of extraneous moisture emitted partial heat and inhibited the oxidation of coal. Previous studies have revealed that with the increase in the moisture content of coal to some extent, an aqueous liquid film is formed on the coal surface, which can inhibit the contact between coal and oxygen and subsequently render an oxygen insulation effect [4,14]. At the same time, a majority of the heat released from coal at a low temperature can be consumed by the evaporation of moisture in coal.…”

Section: Specific Surface Area Analyzermentioning

confidence: 99%

“…Some studies have revealed that external moisture exhibits a clear inhibition effect on coal oxidation; the lower the metamorphic grade of coal, the higher the moisture content, and the stronger the inhibition effect on coal oxidation [12,13]. For internal moisture, physical-state moisture exists on the coal particle surface, and there is a moisture layer on the surface, which reduces the porous structure and specific surface area and affects the oxygen diffusion; hence, the low-temperature oxidation of coal is inhibited [4,14]. On the other hand, chemical-bound moisture can participate in the formation and decomposition of a carbon-oxygen complex during the spontaneous combustion of coal [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Study on the Effect of Extraneous Moisture on the Spontaneous Combustion of Coal and Its Mechanism of Action

Wang

Zhang

et al. 2020

Energies

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It is imperative to have an in-depth understanding of the effect of extraneous moisture on the spontaneous combustion of coal not only for the control and prevention of coal spontaneous combustion in the coal mining industry, but also for the optimization design and application of the technological process. In this study, the type of moisture in a coal body has been redefined for the first time from the perspective of disaster prevention and control, i.e., original occurrence of moisture in the coal matrix and the extraneous moisture from the technological process. A suit of coal bodies with different extraneous moisture was prepared by soaking long-flame coal with a low water content. Using a temperature-programmed oxidation test, the effects of extraneous moisture on the temperature increase rate of coal bodies and the emission characteristics of gaseous products during coal spontaneous combustion were studied. Moreover, combined with the characterization of thermal analysis and of pore structure test, the action the mechanism of extraneous moisture on the coal spontaneous combustion process was also explored. The experimental results indicated that the effect of the extraneous moisture content varied with the development of coal spontaneous combustion. In the slow oxidation stage, extraneous moisture played a physical inhibition role in the coal oxidation. In the accelerated oxidation stage, extraneous moisture exhibited a catalytic effect on the coal–oxygen reaction or directly participated in the reaction. After entering the rapid oxidation stage, a delayed effect appeared. When the coal temperature exceeded 180 °C, the spontaneous combustion characteristics of coals with different initial moisture contents gradually tended to achieved balance.

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Coal weathering and laboratory (artificial) coal oxidation

Cited by 47 publications

References 148 publications

Effect of weathering on physico-chemical properties and combustion behavior of an Indian thermal coal

Effect of weathering on physico-chemical properties and combustion behavior of an Indian thermal coal

Effect of Nitric Acid Modification on Characteristics and Adsorption Properties of Lignite

Study on the Effect of Extraneous Moisture on the Spontaneous Combustion of Coal and Its Mechanism of Action

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